Cyclic wetting-drying alternation has a significant influence on the strength and structure of soils.It is prone to causing soil softening and disintegration,highlighting the importance to improve the soil's resis...Cyclic wetting-drying alternation has a significant influence on the strength and structure of soils.It is prone to causing soil softening and disintegration,highlighting the importance to improve the soil's resistance to disintegration.This paper utilizes a self-developed disintegration test apparatus to analyze the disintegration characteristics of improved red soil under wet-dry cycles,focusing on the disintegration amount and ratio.Furthermore,XRD(X-ray diffraction),SEM(scanning electron microscope),tensile test,and contact angle test are employed to investigate the anti-disintegration behaviors of the improved red soil.The results show that the disintegrating amount and ratio of undisturbed and improved red soil are distinctly different under wet-dry cycles.Linear,stepped,constant and concave but perfect"S"shapes of the disintegrating ratio are observed in the cyclic tests.Cement and lime strengthen the red soil primarily through hydration reaction.The drop experiment confirms that cement plays a crucial role in restraining the disintegration.When the ameliorant content is low,the correlation between pore parameters and disintegration duration of red soil follows the order:mean shape coefficient>fractal dimension>probability entropy>area probability distribution index.With a high ameliorant content,the correlation remains similar,with slightly higher correlation for probability entropy.Under wet-dry cycle conditions,sludge and kaolin can improve the soil through the bonding of clay particles.The improved water repellency greatly enhances the resistance to disintegration of the altered red soil.The research provides valuable insights for the practical application of soil.展开更多
Loess slopes in cold and arid regions are susceptible to shallow soil degradation,which may trigger severe environmental problems related to soil erosion.To address this environmental challenge,this study selected a c...Loess slopes in cold and arid regions are susceptible to shallow soil degradation,which may trigger severe environmental problems related to soil erosion.To address this environmental challenge,this study selected a compound ecological curing agent composed of gellan gum and guar gum for stabilizing shallow loess slopes.Triaxial compression and disintegration tests were employed to comparatively analyze the effects of compound gum content,mass mix ratio,and curing age on the mechanical and disintegration properties of solidified loess.The curing mechanism was analyzed using scanning electron microscopy(SEM),and the ecological protection effect was monitored for a 60-day period.The results indicate that gellan gum,guar gum,and the compound gum can enhance the mechanical and disintegration properties of loess,promote plant growth,and optimize the ecological environment.However,the combination of gellan gum and guar gum proves more effective than using either gellan gum or guar gum alone.Considering the effects on mechanical properties,disintegration performance,and material economy,the disintegration rate of loess decreases by 75.72%compared to plain loess when the compound glue content is 0.5%,the mixing ratio of gellan gum to guar gum is 3:7 and the curing age is 7 days.Meanwhile,the cohesion and internal friction angle increase by 118.06%and 10.97%,respectively.Moreover,the disintegration performance and mechanical properties of the samples first increase and then decrease with the increase in compound glue and the mix ratio and are basically stabilized after the curing age reaches 7d.展开更多
Sulfur-free lignin(SFL),a byproduct of the corn ethanol industry,effectively improves soil strength;however,its inherent solubility limits saline soil treatment in dry-wet environments.To solve this problem,this paper...Sulfur-free lignin(SFL),a byproduct of the corn ethanol industry,effectively improves soil strength;however,its inherent solubility limits saline soil treatment in dry-wet environments.To solve this problem,this paper proposes the selection of a granular SFL(GSFL)with a relatively large particle size,but with its chemical properties retained,to replace the conventional powdered SFL(PSFL).Among the processes of water-induced erosion failure of earthen structures,disintegration is commonly deemed the primary cause.Therefore,the disintegration characteristics of both PSFL-and GSFL-modified soils with 0%,5%,7%,10%,and 12%dosages were tested under dry-wet conditions.Moreover,several physicochemical properties,including the particle size distribution,bound water content,pH value,cation exchange capacity,functional groups,and microstructure,were explored.The results revealed that the water stability of the GSFL-modified soils was greater than that of the PSFL-modified soils.All of the PSFL-modified soils and natural soil completely disintegrated at the first immersion stage,whereas the GSFL-modified soils resisted 7 dry-wet cycles,notably at the 10%dosage.Microscopic analysis revealed that the SFL particle size affected mainly the cementation strength and microstructural homogeneity.Both the GSFL and PSFL particles strengthened the intergranular cementation through ion exchange,electrostatic interactions,and reinforcement effects.However,the PSFL preferentially filled the intragranular pores,causing a nonuniform microstructural arrangement and ineffectively enhancing the disintegration resistance of the saline soil.This preliminary study suggests that the particle size of a soil modifier may affect certain properties of the modified soil,necessitating future focused research.展开更多
The rapid development of military technology has prompted different types of equipment to break the limits of operational domains and emerged through complex interactions to form a vast combat system of systems(CSoS),...The rapid development of military technology has prompted different types of equipment to break the limits of operational domains and emerged through complex interactions to form a vast combat system of systems(CSoS),which can be abstracted as a heterogeneous combat network(HCN).It is of great military significance to study the disintegration strategy of combat networks to achieve the breakdown of the enemy’s CSoS.To this end,this paper proposes an integrated framework called HCN disintegration based on double deep Q-learning(HCN-DDQL).Firstly,the enemy’s CSoS is abstracted as an HCN,and an evaluation index based on the capability and attack costs of nodes is proposed.Meanwhile,a mathematical optimization model for HCN disintegration is established.Secondly,the learning environment and double deep Q-network model of HCN-DDQL are established to train the HCN’s disintegration strategy.Then,based on the learned HCN-DDQL model,an algorithm for calculating the HCN’s optimal disintegration strategy under different states is proposed.Finally,a case study is used to demonstrate the reliability and effectiveness of HCNDDQL,and the results demonstrate that HCN-DDQL can disintegrate HCNs more effectively than baseline methods.展开更多
The disintegration of granite residual soil is especially affected by variations in physical and chemical properties. Serious geologic hazards or engineering problems are closely related to the disintegration of grani...The disintegration of granite residual soil is especially affected by variations in physical and chemical properties. Serious geologic hazards or engineering problems are closely related to the disintegration of granite residual soil in certain areas. Research on the mechanical properties and controlling mechanisms of disintegration has become a hot issue in practical engineering. In this paper, the disintegration characteristics of improved granite residual soil are studied by using a wet and dry cycle disintegration instrument, and the improvement mechanism is analyzed. The results show that the disintegration amounts and disintegration ratios of soil samples treated with different curing agents are obviously different. The disintegration process of improved granite residual soil can be roughly divided into 5 stages:the forcible water intrusion stage, microcrack and fissure development stage, curing and strengthening stage, stable stage, and sudden disintegration stage. The disintegration of granite residual soil is caused by the weakening of the cementation between soil particles under the action of water. When the disintegration force is greater than the anti-disintegration force of soil, the soil will disintegrate. Cement and lime mainly rely on ion exchange agglomeration, the inclusion effect of curing agents on soil particles, the hard coagulation reaction and carbonation to strengthen granite residual soil. Kaolinite mainly depends on the reversibility of its own cementation to improve and strengthen granite residual soil. The reversibility of kaolinite cementation is verified by investigating pure kaolinite with a tensile, soaking, drying and tensile test cycle. Research on the disintegration characteristics and disintegration mechanism of improved granite residual soil is of certain reference value for soil modification.展开更多
Size and quantity of fractured zone and non-fractured zone are controlled by cracks contained in deep rock masses. Zonal disintegration mechanism is strongly dependent on the interaction among cracks. The strong inter...Size and quantity of fractured zone and non-fractured zone are controlled by cracks contained in deep rock masses. Zonal disintegration mechanism is strongly dependent on the interaction among cracks. The strong interaction among cracks is investigated using stress superposition principle and the Chebyshev polynomials expansion of the pseudo-traction. It is found from numerical results that crack nucleation, growth and coalescence lead to failure of deep crack- weakened rock masses. The stress redistribution around the surrounding rock mass induced by unloading excavation is studied. The effect of the excavation time on nucleation, growth, interaction and coalescence of cracks was analyzed. Moreover, the influence of the excavation time on the size and quantity of fractured zone and non-fractured zone was given. When the excavation time is short, zonal disintegration phenomenon may occur in deep rock masses. It is shown from numerical results that the size and quantity of fractured zone increase with decreasing excavation time, and the size and quantity of fractured zone increase with the increasing value of in-situ geostress.展开更多
High-pressure homogenization （HPH） technology was applied as a pretreatment to disintegrate sewage sludge. The effects of homogenization pressure, homogenization cycle number, and total solid content on sludge disin...High-pressure homogenization （HPH） technology was applied as a pretreatment to disintegrate sewage sludge. The effects of homogenization pressure, homogenization cycle number, and total solid content on sludge disintegration were investigated. The sludge disintegration degree （DDCOD）, protein concentration, and polysaccharide concentration increased with the increase of homogenization pressure and homogenization cycle number, and decreased with the increase of sludge total solid （TS） content. The maximum DDCOD of 43.94% was achieved at 80 MPa with four homogenization cycles for a 9.58 g/L TS sludge sample. A HPH sludge disintegration model of DDCOD= kNaPb was established by multivariable linear regression to quantify the effects of homogenization parameters. The homogenization cycle exponent a and homogenization pressure exponent b were 0.4763 and 0.7324 respectively, showing that the effect of homogenization pressure （P） was more significant than that of homogenization cycle number （N）. The value of the rate constant k decreased with the increase of sludge total solid content. The specific energy consumption increased with the increment of sludge disintegration efficiency. Lower specific energy consumption was required for higher total solid content sludge.展开更多
Rock masses without pre-existing macrocracks can usually be considered as granular materials with only microcracks.During the excavation of the tunnels,microcracks may nucleate,grow and propagate through the rock matr...Rock masses without pre-existing macrocracks can usually be considered as granular materials with only microcracks.During the excavation of the tunnels,microcracks may nucleate,grow and propagate through the rock matrix;secondary microcracks may appear,and discontinuous and incompatible deformation of rock masses may occur.The classical continuum elastoplastic theory is not suitable for analyzing discontinuous and incompatible deformation of rock masses.Based on non-Euclidean model of the discontinuous and incompatible deformation of rock masses,the distribution of stresses in the surrounding rock masses in deep tunnels is fluctuant or wave-like.The stress concentration at the tips of microcracks located in vicinity of stress wave crest is comparatively large,which may lead to the unstable growth and coalescence of secondary microcracks,and consequently the occurrence of fractured zones.On the other hand,the stress concentration at the tips of microcracks located around stress wave trough is relatively small,which may lead to the arrest of microcracks,and thus the non-fractured zones.The alternate appearance of stress wave crest and trough thus may induce the alternate occurrence of fractured and non-fractured zones in deep rock masses.For brittle rocks,the dissipated energy of microcrack growth is small,but the elastic strain energy stored in rock masses may be larger than the dissipated energy growths of pre-existing microcracks and secondary microcracks.The sudden release of the residual elastic strain energy may lead to rockburst.Based on this understanding,the criteria of rockburst are established.Furthermore,the relationship between rockbursts and zonal disintegration in the surrounding rock masses around deep tunnels is studied.The influences of the in-situ stresses and the physico-mechanical parameters on the distribution of rockburst zones and the ejection velocity of rock fragments are investigated in detail.展开更多
The zonal disintegration phenomenon （ZDP） is a typical phenomenon in deep block rock masses. In order to investigate the mechanism of ZDP, an improved non-linear Hock-Brown strength criterion and a bi-linear constit...The zonal disintegration phenomenon （ZDP） is a typical phenomenon in deep block rock masses. In order to investigate the mechanism of ZDP, an improved non-linear Hock-Brown strength criterion and a bi-linear constitutive model of rock mass were used to analyze the elasto-plastic stress field of the enclosing rock mass around a deep round tunnel. The radius of the plastic region and stress of the enclosing rock mass were obtained by introducing dimensionless parameters of radial distance. The results show that tunneling in deep rock mass causes a maximum stress zone to appear in the vicinity of the boundary of the elastic and the plastic zone in the surrounding rock mass. Under the compression of a large tangential force and a small radial force, the rock mass in the maximum stress zone was in an approximate uniaxial loading state, which could lead to a split failure in the rock mass.展开更多
The mechanism of the zonal disintegration phenomenon(ZDP) was realized based on the analysis of the stressedstrained state of the rock mass in the vicinity of the maximum stress zone, which resides in the creep instab...The mechanism of the zonal disintegration phenomenon(ZDP) was realized based on the analysis of the stressedstrained state of the rock mass in the vicinity of the maximum stress zone, which resides in the creep instability failure of rock mass due to the development of a plastic zone and transfer of the maximum stress zone within the rock mass.Some characteristic parameters of the ZDP are discussed theoretically.In first instance, the analytical critical depth condition for the occurrence of ZDP was obtained, which depends on the characteristics and stress concentration coefficient of the rock mass.Secondly, based on creep theory, the expression of the outer radius of the undisturbed zones in the deep rock mass was obtained with the use of an improved Burgers rheological model, which indicated that the radius depends on the characteristics of the rock mass and the depth of excavation and increases quasi-linearly with the rise of creep compliance of the rock mass.Finally, the formula for the distance of the most remote fissured zone away from the working periphery was derived, which increases logarithmically with the increase in the ratio of the in-situ stress and ultimate strength of rock mass.The distances between fissured zones are discussed in qualitative terms.展开更多
The microstructure of the RE silicide alloy was studied by SEM. The feature of the phase and the distribution of Ca, P, Al were analyzed, especially the distribution of micro-cracks and its composition were determined...The microstructure of the RE silicide alloy was studied by SEM. The feature of the phase and the distribution of Ca, P, Al were analyzed, especially the distribution of micro-cracks and its composition were determined. The result demonstrates that only a few phosphides contribute to the spontaneous crumbling of the RE silicide alloy by reacting with water and forming oxide or phosphorus oxide. The phosphorus content is not the critical factor of disintegration in the alloy studied.展开更多
Zonal disintegration is a typical static phenomenon of deep rock masses. It has been defined as alternating regions of fractured and relatively intact rock mass that appear around or in front of the working stope duri...Zonal disintegration is a typical static phenomenon of deep rock masses. It has been defined as alternating regions of fractured and relatively intact rock mass that appear around or in front of the working stope during excavation of a deep tunnel. Zonal disintegration phenomenon was successfully demonstrated in the laboratory with 3D tests on analogous gypsum models, two circular cracked zones were observed in the test. The linear Mohr-Coulomb yield criterion was used with a constitutive model that showed linear softening and ideal residual plastic to analyze the elasto-plastic field of the enclosing rock mass around a deep tunnel. The results show that tunneling causes a maximum stress zone to appear between an elastic and plastic zone in the surrounding rock. The zonal disintegration phenomenon is analyzed by considering the stress-strain state of the rock mass in the vicinity of the maximum stress zone. Creep instability failure of the rock due to the development of the plastic zone, and transfer of the maximum stress zone into the rock mass, are the cause of zonal disintegration. An analytical criterion for the critical depth at which zonal disintegration can occur is derived. This depth depends mainly on the character and stress concentration coefficient of the rock mass.展开更多
Benggang erosion is caused by a special type of gully erosion in southern China that seriously endangers the local ecology and environment.In this study,typical Benggang collapsing-wall soils were used as the study ar...Benggang erosion is caused by a special type of gully erosion in southern China that seriously endangers the local ecology and environment.In this study,typical Benggang collapsing-wall soils were used as the study area to investigate the effects of different initial moisture contents and dicranopteris linearis root weight densities,as well as their interactions on disintegration in orthogonal test method.The results showed that the rate of soil disintegration decreased as a linear function of the initial moisture content.The soil disintegration rate tended to rise and then fall as the root weight density increased,reflecting an optimum root weight density of 0.75-1.00 g/100 cm3.The incorporation of dicranopteris linearis roots was most effective for soil consolidation in the shallow layers of soil.In addition,the disintegration rate of the collapsing-wall soils increases as the soil layer deepened.The dicranopteris linearis root system and initial moisture content had an interactive effect that was more pronounced in deeper soils.However,the combined effect of these processes was always dominated by the initial moisture content.Moderate initial soil moisture content(0.20-0.24 g/g)and the addition of a high root density in dicranopteris linearis(0.75-1.00 g/100 cm3)were the optimal combinations that reduced the disintegration rate.In conclusion,maintaining a suitable natural moisture content in collapsing-wall soils and taking measures that use plants to consolidate soil can effectively prevent and control the occurrence of Benggang erosion.The results of this study provided further insight into the factors that influence soil disintegration and offered a scientific basis for soil erosion management in the southern China.展开更多
To investigate the zonal disintegration form of the surrounding rock in deep tunnels,model tests were performed in the simulation set-up of fracture mechanism and support technology of surrounding rock in deep tunnel....To investigate the zonal disintegration form of the surrounding rock in deep tunnels,model tests were performed in the simulation set-up of fracture mechanism and support technology of surrounding rock in deep tunnel.The test results illustrate that the first fracture of the surrounding rock occurred at the intersection of the tunnel floor and the side wall.After more serious destruction,the side wall and the vault were destroyed.Although the fracture width of each surrounding rock mass was distinct,they were relatively uniform with a nearly continuous fracture form.The width of the split bodies of the model tunnels(i.e.,the annular zonal disintegration area)developed with an increasing load.It was observed from the fitting curves of the data that all radial strain values of the surrounding rock were more symmetric with a smooth fitting curve,and the maximum value occurred near the tunnel wall before reducing instantly.The circumferential strain values were dispersed and the data were inconsistent with the fitting curve,which caused some data to be unreliable.The phenomenon of zonal disintegration was primarily caused by radial tension strain of the surrounding rock.This phenomenon would not extend indefinitely as the rupture range would be limited to a certain extent,because the maximum radial tension strain of the surrounding rock was less than the limiting value.展开更多
A new non-Euclidean continuum damage model is proposed to investigate the zonal disintegration phenomenon of the surrounding rocks around deep spherical tunnels under hydrostatic pressure condition as well as the tota...A new non-Euclidean continuum damage model is proposed to investigate the zonal disintegration phenomenon of the surrounding rocks around deep spherical tunnels under hydrostatic pressure condition as well as the total elastic stress field distributions.The elastic stress fields of the surrounding rocks around deep spherical tunnels under hydrostatic pressure condition axe obtained.If the elastic stresses of the surrounding rocks satisfy the strength criterion of the deep rock masses,the number,size and location of fractured and nonfractured zones are determined.The effect of physico-mechanical parameters of the surrounding rocks on the zonal disintegration phenomenon is studied and numerical computation is carried out.It is found from numerical results that the number,size and location of fractured and non-fractured zones are sensitive to the physico-mechanical parameters of the surrounding rocks.展开更多
Disintegration of rock is one of the primary processes of soil formation and geomorphology and is affected considerably by water and heat.This study focused on the disintegration characteristics under laboratory condi...Disintegration of rock is one of the primary processes of soil formation and geomorphology and is affected considerably by water and heat.This study focused on the disintegration characteristics under laboratory conditions of typical purple mudstone from the Tuodian group of Jurassic red beds(J3t) in Tuodian Town,Shuangbai county,Yunnan Province of southern China.The fresh mudstone was subjected to alternating applications of water,heat and hydrothermal interaction during five treatments:wetting-drying(WD),saturation(ST),refrigeration-heating(RH),a combination of wetting-drying and refrigeration-heating(WDRH),and a combination of saturation and refrigeration-heating(STRH).Each treatment was run in twenty-four cycles.The results showed that there are three types of disintegration:collapsing disintegration,exfoliation disintegration and imperceptible disintegration.The cumulative disintegration rate(percentage of cumulative disintegrated mass to the initiative sample mass passed through a 2 mm sieve) produced a 'S'-shape function when related to treatment cycle time and closely fit a logistic model(R2 > 0.99).The rank order of the cumulative disintegration rate resulting from the five treatments was as the following:WDRH > STRH > ST > WD > RH.Because of alternating periods of moisture and dryness,WD caused the most disintegration,while RH alone resulted in imperceptible disintegration.Additionally,there was a negative correlation between the disintegration rate of each treatment cycle(percentage of disintegrated mass to the treated sample mass) and treatment cycle number.There was a positive correlation between this rate and temperature change under moist conditions,indicating that a change in temperature greatly accelerates the disintegration of parent rock when water was supplied.展开更多
The effects of two solid-based hydrogen peroxides sodium percarbonate(SPC) and calcium peroxide(CP)on waste activated sludge(WAS) disintegration were investigated. Both oxidants achieved efficient WAS disintegration f...The effects of two solid-based hydrogen peroxides sodium percarbonate(SPC) and calcium peroxide(CP)on waste activated sludge(WAS) disintegration were investigated. Both oxidants achieved efficient WAS disintegration for the synergistic effect of alkaline and oxidation. The strong alkaline condition led to the leakage of ammonia and the existence of abundant calcium ions accelerated the fixation of phosphorus via precipitation in CP WAS disintegration process. However, the spongy-like layer and low p H condition retarded the release of gaseous ammonia in SPC group. Hydroxyl radical was the main oxygen reactive species in SPC approaches which were more intense than CP by electron spin resonance(ESR) analysis.CP treated WAS contented more small particle size matter and total suspended solids(TSS) increased dramatically. In conclusion, CP pretreated sludge was more suitable for fertilization, while SPC was in favor of anaerobic digestion. This study clarified the differences between these two oxidants and their intermediates on nutrients release in sludge disintegration.展开更多
In this study, it was assumed that three-dimensional penny-shaped cracks existed in deep rock masses. A new non-Euclidean model was established, in which the effects of penny- shaped cracks and axial in-situ stress on...In this study, it was assumed that three-dimensional penny-shaped cracks existed in deep rock masses. A new non-Euclidean model was established, in which the effects of penny- shaped cracks and axial in-situ stress on zonal disintegration of deep rock masses were taken into account. Based on the non-Euclidean model, the stress intensity factors at tips of the penny- shaped cracks were determined. The strain energy density factor was applied to investigate the occurrence of fractured zones. It was observed from the numerical results that the magnitude and location of fractured zones were sensitive to micro- and macro-mechanical parameters, as well as the value of in-situ stress. The numerical results were in good agreement with the experimental data.展开更多
Total disintegration events produced by 4.5 A GeV/c ^16O-AgBr interactions are analysed to investigate the characteristics of secondary charged particles produced in such collisions. The multiplicity distributions of ...Total disintegration events produced by 4.5 A GeV/c ^16O-AgBr interactions are analysed to investigate the characteristics of secondary charged particles produced in such collisions. The multiplicity distributions of grey, black, and relativistic charged particles can be well represented by Gaussian distribution. The average multiplicity of grey particles is found to increase with the mass of projectile increasing, while that of black particles is found to decrease with the mass of projectile increasing. This result is in good agreement with the prediction of fireball model. Finally, the linear dependence between grey and black particles is observed, but there is no distinct dependence between the production of relativistic charged particles and the target excitation.展开更多
The main pathways of primary sludge(PS)ultrasonic disintegration were analyzed at the sonication frequency of 20 kH z and the thermal effect on PS disintegration was investigated.By adding Na HCO3as a scavenger to ent...The main pathways of primary sludge(PS)ultrasonic disintegration were analyzed at the sonication frequency of 20 kH z and the thermal effect on PS disintegration was investigated.By adding Na HCO3as a scavenger to entrap the free hydroxyl radicals,cavitation contributed to 82.91%of the total sonication effect.The power consumed by temperature rising accounted for more than40%of ultrasound power input at the power density of 0.215 W/m L and the sonication time of 10 min.With the thermal insulation of polyfoam coating during sonication,a 18.37%of soluble chemical oxygen demand(SCOD)increment was observed.With the process of pre-heating the PS before sonication,64.15%of SCOD increment was achieved.Compared with the particle size of 13.77μm for the sonicated PS,the sludge mean particle size decreased to 12.83 and11.98μm by applying polyfoam coating and pre-heating the PS to enhance the cavitation and thermal effect.It suggested that if thermal energy consumption was relieved during the sonication process of PS,more energy could be used to disintegrate the sludge.展开更多
基金financially supported by the National Natural Science Foundation of China(Grant No.42102303)the Natural Science Foundation of Yunnan Province,China(Grant No.202401CF070174)the Xingdian Talent Support Program(Grant No.C619300A130).
文摘Cyclic wetting-drying alternation has a significant influence on the strength and structure of soils.It is prone to causing soil softening and disintegration,highlighting the importance to improve the soil's resistance to disintegration.This paper utilizes a self-developed disintegration test apparatus to analyze the disintegration characteristics of improved red soil under wet-dry cycles,focusing on the disintegration amount and ratio.Furthermore,XRD(X-ray diffraction),SEM(scanning electron microscope),tensile test,and contact angle test are employed to investigate the anti-disintegration behaviors of the improved red soil.The results show that the disintegrating amount and ratio of undisturbed and improved red soil are distinctly different under wet-dry cycles.Linear,stepped,constant and concave but perfect"S"shapes of the disintegrating ratio are observed in the cyclic tests.Cement and lime strengthen the red soil primarily through hydration reaction.The drop experiment confirms that cement plays a crucial role in restraining the disintegration.When the ameliorant content is low,the correlation between pore parameters and disintegration duration of red soil follows the order:mean shape coefficient>fractal dimension>probability entropy>area probability distribution index.With a high ameliorant content,the correlation remains similar,with slightly higher correlation for probability entropy.Under wet-dry cycle conditions,sludge and kaolin can improve the soil through the bonding of clay particles.The improved water repellency greatly enhances the resistance to disintegration of the altered red soil.The research provides valuable insights for the practical application of soil.
基金funded by the Natural Science Foundation of Inner Mongolia Autonomous Region(2023JQ03,2023QN05014)the Youth Science and Technology Talents Project of Autonomous Region Colleges and Universities(NJYT22108)。
文摘Loess slopes in cold and arid regions are susceptible to shallow soil degradation,which may trigger severe environmental problems related to soil erosion.To address this environmental challenge,this study selected a compound ecological curing agent composed of gellan gum and guar gum for stabilizing shallow loess slopes.Triaxial compression and disintegration tests were employed to comparatively analyze the effects of compound gum content,mass mix ratio,and curing age on the mechanical and disintegration properties of solidified loess.The curing mechanism was analyzed using scanning electron microscopy(SEM),and the ecological protection effect was monitored for a 60-day period.The results indicate that gellan gum,guar gum,and the compound gum can enhance the mechanical and disintegration properties of loess,promote plant growth,and optimize the ecological environment.However,the combination of gellan gum and guar gum proves more effective than using either gellan gum or guar gum alone.Considering the effects on mechanical properties,disintegration performance,and material economy,the disintegration rate of loess decreases by 75.72%compared to plain loess when the compound glue content is 0.5%,the mixing ratio of gellan gum to guar gum is 3:7 and the curing age is 7 days.Meanwhile,the cohesion and internal friction angle increase by 118.06%and 10.97%,respectively.Moreover,the disintegration performance and mechanical properties of the samples first increase and then decrease with the increase in compound glue and the mix ratio and are basically stabilized after the curing age reaches 7d.
基金funded by the National Natural Science Foundation of China(Grant Nos.42330708 and 42302329).
文摘Sulfur-free lignin(SFL),a byproduct of the corn ethanol industry,effectively improves soil strength;however,its inherent solubility limits saline soil treatment in dry-wet environments.To solve this problem,this paper proposes the selection of a granular SFL(GSFL)with a relatively large particle size,but with its chemical properties retained,to replace the conventional powdered SFL(PSFL).Among the processes of water-induced erosion failure of earthen structures,disintegration is commonly deemed the primary cause.Therefore,the disintegration characteristics of both PSFL-and GSFL-modified soils with 0%,5%,7%,10%,and 12%dosages were tested under dry-wet conditions.Moreover,several physicochemical properties,including the particle size distribution,bound water content,pH value,cation exchange capacity,functional groups,and microstructure,were explored.The results revealed that the water stability of the GSFL-modified soils was greater than that of the PSFL-modified soils.All of the PSFL-modified soils and natural soil completely disintegrated at the first immersion stage,whereas the GSFL-modified soils resisted 7 dry-wet cycles,notably at the 10%dosage.Microscopic analysis revealed that the SFL particle size affected mainly the cementation strength and microstructural homogeneity.Both the GSFL and PSFL particles strengthened the intergranular cementation through ion exchange,electrostatic interactions,and reinforcement effects.However,the PSFL preferentially filled the intragranular pores,causing a nonuniform microstructural arrangement and ineffectively enhancing the disintegration resistance of the saline soil.This preliminary study suggests that the particle size of a soil modifier may affect certain properties of the modified soil,necessitating future focused research.
基金supported by the National Natural Science Foundation of China(7200120972231011+2 种基金72071206)the Science and Technology Innovative Research Team in Higher Educational Institutions of Hunan Province(2020RC4046)the Science Foundation for Outstanding Youth Scholars of Hunan Province(2022JJ20047).
文摘The rapid development of military technology has prompted different types of equipment to break the limits of operational domains and emerged through complex interactions to form a vast combat system of systems(CSoS),which can be abstracted as a heterogeneous combat network(HCN).It is of great military significance to study the disintegration strategy of combat networks to achieve the breakdown of the enemy’s CSoS.To this end,this paper proposes an integrated framework called HCN disintegration based on double deep Q-learning(HCN-DDQL).Firstly,the enemy’s CSoS is abstracted as an HCN,and an evaluation index based on the capability and attack costs of nodes is proposed.Meanwhile,a mathematical optimization model for HCN disintegration is established.Secondly,the learning environment and double deep Q-network model of HCN-DDQL are established to train the HCN’s disintegration strategy.Then,based on the learned HCN-DDQL model,an algorithm for calculating the HCN’s optimal disintegration strategy under different states is proposed.Finally,a case study is used to demonstrate the reliability and effectiveness of HCNDDQL,and the results demonstrate that HCN-DDQL can disintegrate HCNs more effectively than baseline methods.
基金supported by the National Natural Science Foundation of China (Nos. 41877228, 41877229 and 42102303)Guangdong Basic and Applied Basic Research Foundation (Nos. 2018B030311066 and 2019A1515010554)+1 种基金China Postdoctoral Science Foundation (No. 2019M663241)Science and Technology Program of Guangzhou, China (No. 201904010136)。
文摘The disintegration of granite residual soil is especially affected by variations in physical and chemical properties. Serious geologic hazards or engineering problems are closely related to the disintegration of granite residual soil in certain areas. Research on the mechanical properties and controlling mechanisms of disintegration has become a hot issue in practical engineering. In this paper, the disintegration characteristics of improved granite residual soil are studied by using a wet and dry cycle disintegration instrument, and the improvement mechanism is analyzed. The results show that the disintegration amounts and disintegration ratios of soil samples treated with different curing agents are obviously different. The disintegration process of improved granite residual soil can be roughly divided into 5 stages:the forcible water intrusion stage, microcrack and fissure development stage, curing and strengthening stage, stable stage, and sudden disintegration stage. The disintegration of granite residual soil is caused by the weakening of the cementation between soil particles under the action of water. When the disintegration force is greater than the anti-disintegration force of soil, the soil will disintegrate. Cement and lime mainly rely on ion exchange agglomeration, the inclusion effect of curing agents on soil particles, the hard coagulation reaction and carbonation to strengthen granite residual soil. Kaolinite mainly depends on the reversibility of its own cementation to improve and strengthen granite residual soil. The reversibility of kaolinite cementation is verified by investigating pure kaolinite with a tensile, soaking, drying and tensile test cycle. Research on the disintegration characteristics and disintegration mechanism of improved granite residual soil is of certain reference value for soil modification.
基金supported by the National Natural Science Foundation of China(Nos.50490275 and 50778184)
文摘Size and quantity of fractured zone and non-fractured zone are controlled by cracks contained in deep rock masses. Zonal disintegration mechanism is strongly dependent on the interaction among cracks. The strong interaction among cracks is investigated using stress superposition principle and the Chebyshev polynomials expansion of the pseudo-traction. It is found from numerical results that crack nucleation, growth and coalescence lead to failure of deep crack- weakened rock masses. The stress redistribution around the surrounding rock mass induced by unloading excavation is studied. The effect of the excavation time on nucleation, growth, interaction and coalescence of cracks was analyzed. Moreover, the influence of the excavation time on the size and quantity of fractured zone and non-fractured zone was given. When the excavation time is short, zonal disintegration phenomenon may occur in deep rock masses. It is shown from numerical results that the size and quantity of fractured zone increase with decreasing excavation time, and the size and quantity of fractured zone increase with the increasing value of in-situ geostress.
基金supported by the China-Israel Joint Research Program, MOST of Chinathe National Natural Science Foundation of China (No. 51178047)the Foundation of Key Laboratory for Solid Waste Management and Environment Safety,Ministry of Education of China (No. SWMES 2010-2)
文摘High-pressure homogenization （HPH） technology was applied as a pretreatment to disintegrate sewage sludge. The effects of homogenization pressure, homogenization cycle number, and total solid content on sludge disintegration were investigated. The sludge disintegration degree （DDCOD）, protein concentration, and polysaccharide concentration increased with the increase of homogenization pressure and homogenization cycle number, and decreased with the increase of sludge total solid （TS） content. The maximum DDCOD of 43.94% was achieved at 80 MPa with four homogenization cycles for a 9.58 g/L TS sludge sample. A HPH sludge disintegration model of DDCOD= kNaPb was established by multivariable linear regression to quantify the effects of homogenization parameters. The homogenization cycle exponent a and homogenization pressure exponent b were 0.4763 and 0.7324 respectively, showing that the effect of homogenization pressure （P） was more significant than that of homogenization cycle number （N）. The value of the rate constant k decreased with the increase of sludge total solid content. The specific energy consumption increased with the increment of sludge disintegration efficiency. Lower specific energy consumption was required for higher total solid content sludge.
基金Supported by the National Natural Science Foundation of China (51078371,51021001)the Natural Science Foundation Project of CQ CSTC (2009BA4046,2009AB6194)
文摘Rock masses without pre-existing macrocracks can usually be considered as granular materials with only microcracks.During the excavation of the tunnels,microcracks may nucleate,grow and propagate through the rock matrix;secondary microcracks may appear,and discontinuous and incompatible deformation of rock masses may occur.The classical continuum elastoplastic theory is not suitable for analyzing discontinuous and incompatible deformation of rock masses.Based on non-Euclidean model of the discontinuous and incompatible deformation of rock masses,the distribution of stresses in the surrounding rock masses in deep tunnels is fluctuant or wave-like.The stress concentration at the tips of microcracks located in vicinity of stress wave crest is comparatively large,which may lead to the unstable growth and coalescence of secondary microcracks,and consequently the occurrence of fractured zones.On the other hand,the stress concentration at the tips of microcracks located around stress wave trough is relatively small,which may lead to the arrest of microcracks,and thus the non-fractured zones.The alternate appearance of stress wave crest and trough thus may induce the alternate occurrence of fractured and non-fractured zones in deep rock masses.For brittle rocks,the dissipated energy of microcrack growth is small,but the elastic strain energy stored in rock masses may be larger than the dissipated energy growths of pre-existing microcracks and secondary microcracks.The sudden release of the residual elastic strain energy may lead to rockburst.Based on this understanding,the criteria of rockburst are established.Furthermore,the relationship between rockbursts and zonal disintegration in the surrounding rock masses around deep tunnels is studied.The influences of the in-situ stresses and the physico-mechanical parameters on the distribution of rockburst zones and the ejection velocity of rock fragments are investigated in detail.
基金Projects 50525825, 50490275 and 90815010 supported by the National Natural Science Foundation of China2009CB724608 by the National BasicResearch Program of China
文摘The zonal disintegration phenomenon （ZDP） is a typical phenomenon in deep block rock masses. In order to investigate the mechanism of ZDP, an improved non-linear Hock-Brown strength criterion and a bi-linear constitutive model of rock mass were used to analyze the elasto-plastic stress field of the enclosing rock mass around a deep round tunnel. The radius of the plastic region and stress of the enclosing rock mass were obtained by introducing dimensionless parameters of radial distance. The results show that tunneling in deep rock mass causes a maximum stress zone to appear in the vicinity of the boundary of the elastic and the plastic zone in the surrounding rock mass. Under the compression of a large tangential force and a small radial force, the rock mass in the maximum stress zone was in an approximate uniaxial loading state, which could lead to a split failure in the rock mass.
基金Projects 50525825 supported by the National Natural Science Foundation of China2009CB724608 by the National Basic Research Program of China
文摘The mechanism of the zonal disintegration phenomenon(ZDP) was realized based on the analysis of the stressedstrained state of the rock mass in the vicinity of the maximum stress zone, which resides in the creep instability failure of rock mass due to the development of a plastic zone and transfer of the maximum stress zone within the rock mass.Some characteristic parameters of the ZDP are discussed theoretically.In first instance, the analytical critical depth condition for the occurrence of ZDP was obtained, which depends on the characteristics and stress concentration coefficient of the rock mass.Secondly, based on creep theory, the expression of the outer radius of the undisturbed zones in the deep rock mass was obtained with the use of an improved Burgers rheological model, which indicated that the radius depends on the characteristics of the rock mass and the depth of excavation and increases quasi-linearly with the rise of creep compliance of the rock mass.Finally, the formula for the distance of the most remote fissured zone away from the working periphery was derived, which increases logarithmically with the increase in the ratio of the in-situ stress and ultimate strength of rock mass.The distances between fissured zones are discussed in qualitative terms.
文摘The microstructure of the RE silicide alloy was studied by SEM. The feature of the phase and the distribution of Ca, P, Al were analyzed, especially the distribution of micro-cracks and its composition were determined. The result demonstrates that only a few phosphides contribute to the spontaneous crumbling of the RE silicide alloy by reacting with water and forming oxide or phosphorus oxide. The phosphorus content is not the critical factor of disintegration in the alloy studied.
基金Projects 50490275 and 50525825 supported by the National Natural Science Foundation of China
文摘Zonal disintegration is a typical static phenomenon of deep rock masses. It has been defined as alternating regions of fractured and relatively intact rock mass that appear around or in front of the working stope during excavation of a deep tunnel. Zonal disintegration phenomenon was successfully demonstrated in the laboratory with 3D tests on analogous gypsum models, two circular cracked zones were observed in the test. The linear Mohr-Coulomb yield criterion was used with a constitutive model that showed linear softening and ideal residual plastic to analyze the elasto-plastic field of the enclosing rock mass around a deep tunnel. The results show that tunneling causes a maximum stress zone to appear between an elastic and plastic zone in the surrounding rock. The zonal disintegration phenomenon is analyzed by considering the stress-strain state of the rock mass in the vicinity of the maximum stress zone. Creep instability failure of the rock due to the development of the plastic zone, and transfer of the maximum stress zone into the rock mass, are the cause of zonal disintegration. An analytical criterion for the critical depth at which zonal disintegration can occur is derived. This depth depends mainly on the character and stress concentration coefficient of the rock mass.
基金supported by the Special Projects of the Central Government Guiding Local Science and Technology Development in China(Guike.ZY21195022)the National Natural Science Foundation of China(No.42007055 and 42107350)。
文摘Benggang erosion is caused by a special type of gully erosion in southern China that seriously endangers the local ecology and environment.In this study,typical Benggang collapsing-wall soils were used as the study area to investigate the effects of different initial moisture contents and dicranopteris linearis root weight densities,as well as their interactions on disintegration in orthogonal test method.The results showed that the rate of soil disintegration decreased as a linear function of the initial moisture content.The soil disintegration rate tended to rise and then fall as the root weight density increased,reflecting an optimum root weight density of 0.75-1.00 g/100 cm3.The incorporation of dicranopteris linearis roots was most effective for soil consolidation in the shallow layers of soil.In addition,the disintegration rate of the collapsing-wall soils increases as the soil layer deepened.The dicranopteris linearis root system and initial moisture content had an interactive effect that was more pronounced in deeper soils.However,the combined effect of these processes was always dominated by the initial moisture content.Moderate initial soil moisture content(0.20-0.24 g/g)and the addition of a high root density in dicranopteris linearis(0.75-1.00 g/100 cm3)were the optimal combinations that reduced the disintegration rate.In conclusion,maintaining a suitable natural moisture content in collapsing-wall soils and taking measures that use plants to consolidate soil can effectively prevent and control the occurrence of Benggang erosion.The results of this study provided further insight into the factors that influence soil disintegration and offered a scientific basis for soil erosion management in the southern China.
基金This work was financially supported by the Chinese National key R&D project(No.2016YFC0801402)the Chinese National Natural Science Foundation Project(No.51627804).
文摘To investigate the zonal disintegration form of the surrounding rock in deep tunnels,model tests were performed in the simulation set-up of fracture mechanism and support technology of surrounding rock in deep tunnel.The test results illustrate that the first fracture of the surrounding rock occurred at the intersection of the tunnel floor and the side wall.After more serious destruction,the side wall and the vault were destroyed.Although the fracture width of each surrounding rock mass was distinct,they were relatively uniform with a nearly continuous fracture form.The width of the split bodies of the model tunnels(i.e.,the annular zonal disintegration area)developed with an increasing load.It was observed from the fitting curves of the data that all radial strain values of the surrounding rock were more symmetric with a smooth fitting curve,and the maximum value occurred near the tunnel wall before reducing instantly.The circumferential strain values were dispersed and the data were inconsistent with the fitting curve,which caused some data to be unreliable.The phenomenon of zonal disintegration was primarily caused by radial tension strain of the surrounding rock.This phenomenon would not extend indefinitely as the rupture range would be limited to a certain extent,because the maximum radial tension strain of the surrounding rock was less than the limiting value.
基金supported by the National Natural Science Foundation of China(Nos.51279218,51021001 and 51078371)Natural Science Foundation Project of CQ CSTC(No.CSTC,2009BA4046)the Fundamental Research Funds forthe Central Universities(No.CDJZR10205501)
文摘A new non-Euclidean continuum damage model is proposed to investigate the zonal disintegration phenomenon of the surrounding rocks around deep spherical tunnels under hydrostatic pressure condition as well as the total elastic stress field distributions.The elastic stress fields of the surrounding rocks around deep spherical tunnels under hydrostatic pressure condition axe obtained.If the elastic stresses of the surrounding rocks satisfy the strength criterion of the deep rock masses,the number,size and location of fractured and nonfractured zones are determined.The effect of physico-mechanical parameters of the surrounding rocks on the zonal disintegration phenomenon is studied and numerical computation is carried out.It is found from numerical results that the number,size and location of fractured and non-fractured zones are sensitive to the physico-mechanical parameters of the surrounding rocks.
基金supported by National Natural Science Foundation of China (Grant No.40971168)National Basic Research Program of China (973 Program) (Grant No. 2007CB407206)
文摘Disintegration of rock is one of the primary processes of soil formation and geomorphology and is affected considerably by water and heat.This study focused on the disintegration characteristics under laboratory conditions of typical purple mudstone from the Tuodian group of Jurassic red beds(J3t) in Tuodian Town,Shuangbai county,Yunnan Province of southern China.The fresh mudstone was subjected to alternating applications of water,heat and hydrothermal interaction during five treatments:wetting-drying(WD),saturation(ST),refrigeration-heating(RH),a combination of wetting-drying and refrigeration-heating(WDRH),and a combination of saturation and refrigeration-heating(STRH).Each treatment was run in twenty-four cycles.The results showed that there are three types of disintegration:collapsing disintegration,exfoliation disintegration and imperceptible disintegration.The cumulative disintegration rate(percentage of cumulative disintegrated mass to the initiative sample mass passed through a 2 mm sieve) produced a 'S'-shape function when related to treatment cycle time and closely fit a logistic model(R2 > 0.99).The rank order of the cumulative disintegration rate resulting from the five treatments was as the following:WDRH > STRH > ST > WD > RH.Because of alternating periods of moisture and dryness,WD caused the most disintegration,while RH alone resulted in imperceptible disintegration.Additionally,there was a negative correlation between the disintegration rate of each treatment cycle(percentage of disintegrated mass to the treated sample mass) and treatment cycle number.There was a positive correlation between this rate and temperature change under moist conditions,indicating that a change in temperature greatly accelerates the disintegration of parent rock when water was supplied.
基金financially supported by the National Natural Science Foundation of China (No. 51978201)the State Key Laboratory of Urban Water Resource and Environment (No.2020DX08)。
文摘The effects of two solid-based hydrogen peroxides sodium percarbonate(SPC) and calcium peroxide(CP)on waste activated sludge(WAS) disintegration were investigated. Both oxidants achieved efficient WAS disintegration for the synergistic effect of alkaline and oxidation. The strong alkaline condition led to the leakage of ammonia and the existence of abundant calcium ions accelerated the fixation of phosphorus via precipitation in CP WAS disintegration process. However, the spongy-like layer and low p H condition retarded the release of gaseous ammonia in SPC group. Hydroxyl radical was the main oxygen reactive species in SPC approaches which were more intense than CP by electron spin resonance(ESR) analysis.CP treated WAS contented more small particle size matter and total suspended solids(TSS) increased dramatically. In conclusion, CP pretreated sludge was more suitable for fertilization, while SPC was in favor of anaerobic digestion. This study clarified the differences between these two oxidants and their intermediates on nutrients release in sludge disintegration.
基金supported by the 973 Project(No.2014CB046903)the National Natural Science Foundation of China(Nos.51325903 and 51279218)the Natural Science Foundation Project of CQ CSTC(Nos.CSTC2013KJRC-1JRCCJ30001 and CSTC2013JCYJYS0005)
文摘In this study, it was assumed that three-dimensional penny-shaped cracks existed in deep rock masses. A new non-Euclidean model was established, in which the effects of penny- shaped cracks and axial in-situ stress on zonal disintegration of deep rock masses were taken into account. Based on the non-Euclidean model, the stress intensity factors at tips of the penny- shaped cracks were determined. The strain energy density factor was applied to investigate the occurrence of fractured zones. It was observed from the numerical results that the magnitude and location of fractured zones were sensitive to micro- and macro-mechanical parameters, as well as the value of in-situ stress. The numerical results were in good agreement with the experimental data.
基金Project supported by the National Natural Science Foundation of China （Grant No 10475054）, the Major Science and Technology Foundation of Ministry of Education of China （Grant No 205026）, the Natural Science Foundation of Shanxi Province, China （Grant No 20021007） and Shanxi Provincial Foundation for Returned Scholars, China （Grant No 20031046）.
文摘Total disintegration events produced by 4.5 A GeV/c ^16O-AgBr interactions are analysed to investigate the characteristics of secondary charged particles produced in such collisions. The multiplicity distributions of grey, black, and relativistic charged particles can be well represented by Gaussian distribution. The average multiplicity of grey particles is found to increase with the mass of projectile increasing, while that of black particles is found to decrease with the mass of projectile increasing. This result is in good agreement with the prediction of fireball model. Finally, the linear dependence between grey and black particles is observed, but there is no distinct dependence between the production of relativistic charged particles and the target excitation.
基金National Natural Science Foundation of China(No.51478099)Scientific Research Foundation for Returned Overseas Chinese Scholars of China(No.SEM-11W11329)
文摘The main pathways of primary sludge(PS)ultrasonic disintegration were analyzed at the sonication frequency of 20 kH z and the thermal effect on PS disintegration was investigated.By adding Na HCO3as a scavenger to entrap the free hydroxyl radicals,cavitation contributed to 82.91%of the total sonication effect.The power consumed by temperature rising accounted for more than40%of ultrasound power input at the power density of 0.215 W/m L and the sonication time of 10 min.With the thermal insulation of polyfoam coating during sonication,a 18.37%of soluble chemical oxygen demand(SCOD)increment was observed.With the process of pre-heating the PS before sonication,64.15%of SCOD increment was achieved.Compared with the particle size of 13.77μm for the sonicated PS,the sludge mean particle size decreased to 12.83 and11.98μm by applying polyfoam coating and pre-heating the PS to enhance the cavitation and thermal effect.It suggested that if thermal energy consumption was relieved during the sonication process of PS,more energy could be used to disintegrate the sludge.
