Rammed earth wall technique is one of the local widespread traditional construction methods, and it has superior physical property and ecological protection characteristic. When contemporary raw-soil building is repla...Rammed earth wall technique is one of the local widespread traditional construction methods, and it has superior physical property and ecological protection characteristic. When contemporary raw-soil building is replaced by industry building, the hometown building culture is perishing gradually. In order to inherit and develop the Hanzhong local building, rammed earth wall in Taiyangling and Cangshe hometown is investigated, and the characteristics and construction techniques of the local rammed earth wall are concluded. According to the construction problems, the improvement suggestions are put forward, which establishes the foundation to investigate rammed earth wall further, and guide Rural House construction.展开更多
The scientific evaluation on heat insulation and preservation capacity of rammed earth construction can provide an effective evidence for its superiority in preserving thermal environment of the construction. By takin...The scientific evaluation on heat insulation and preservation capacity of rammed earth construction can provide an effective evidence for its superiority in preserving thermal environment of the construction. By taking an eco-hotel in Zhejiang Anji County as the research object, 33 test points have been set. The indoor and outdoor air temperature of eco-hotel and the surface temperature of building envelopes had been recorded by using data acquisition instrument, temperature transmitter and other equipments from January 27 to February 2 in 2007. Then, the data of a period had been selected for comparison and analysis and the results had been obtained as follows. In January when the temperature difference between day and night in Anji was not large, without particular thermal insulation measures and equipments, the indoor temperature of eco-hotel fluctuated very little, showing that rammed earth construction was of obvious capacity for heat preservation and insulation, that its heat stability was evident and that it could ensure excellent indoor thermal environment.展开更多
Based on the idea of optimization design of pile type, the two kinds of the typical pile type are selected, which containing flexibility pile (e.g. rammed cement-soil pile is for short RCSP), and rigid pile (e.g. ceme...Based on the idea of optimization design of pile type, the two kinds of the typical pile type are selected, which containing flexibility pile (e.g. rammed cement-soil pile is for short RCSP), and rigid pile (e.g. cement-flyash-gravel pile is for short CFGP). The three kinds of the composite foundation are designed, which are CFGP, CFG long pile and CFG short pile (for short CFGLP-CFGSP), CFG long-short pile and rammed cement-soil short pile (for short CFGLP-RCSSP). Natural earthquake is simulated by using the engineering blasting;the dynamic characteristics and dynamic response of the composite foundation are studied through field test. CFGLP-RCSSP is closed to linear relation. The bearing capacity of the four composite foundation of the CFGP, CFGLP-CFGSP, and CFGLP-RCSSP in the site are 225 kPa, 179 kPa, and 197 kPa, separately increases 150%, 98.8% and 119% compared to the natural foundation. The vibration main frequency is mainly depended on properties of foundation soil and piles between vibration source and measuring point, pilling load value. Horizontal vibration main frequency greater than the vertical vibration main frequency and the vertical vibration main frequency close to the first-order natural frequency of composite foundation. With the pilling load increasing, the CFGLP-RCSSP pile composite foundation combined frequency decreased. Under the same blast energy, the acceleration peak on the CFG pile composite foundation is less than CFGLP-CFGSP the corresponding values, as the load increases, the peak acceleration gently. CFG pile composite foundation is favorable on seismic. The distribution of peak acceleration is consistent within 4 m from pile top in the CFGLP_RCSSP composite foundation. The maximum of the horizontal acceleration peak along the pile body occurs at a distance of pile top 4 m or the pile top, and that of vertical acceleration peak occurred at a pile top.展开更多
The authors regret that in the paper of Baldovino et al.(2019),published in Journal of Rock Mechanics and Geotechnical Engineering(JRMGE),Eq.(2)must be corrected.Eq.(2)in the original paper describes a formula to calc...The authors regret that in the paper of Baldovino et al.(2019),published in Journal of Rock Mechanics and Geotechnical Engineering(JRMGE),Eq.(2)must be corrected.Eq.(2)in the original paper describes a formula to calculate the unconfined compressive strength(q_u).But Authors wrote it as if it were the formula for calculating the split tensile strength(qt).To amend this error,Eq.(1)and Eq.(2)are the correct expressions for q_u and q_t measurements,respectively.展开更多
The cavity characteristics in liquid-filled containers caused by high-velocity impacts represent an important area of research in hydrodynamic ram phenomena.The dynamic expansion of the cavity induces liquid pressure ...The cavity characteristics in liquid-filled containers caused by high-velocity impacts represent an important area of research in hydrodynamic ram phenomena.The dynamic expansion of the cavity induces liquid pressure variations,potentially causing catastrophic damage to the container.Current studies mainly focus on non-deforming projectiles,such as fragments,with limited exploration of shaped charge jets.In this paper,a uniquely experimental system was designed to record cavity profiles in behind-armor liquid-filled containers subjected to shaped charge jet impacts.The impact process was then numerically reproduced using the explicit simulation program ANSYS LS-DYNA with the Structured Arbitrary Lagrangian-Eulerian(S-ALE)solver.The formation mechanism,along with the dimensional and shape evolution of the cavity was investigated.Additionally,the influence of the impact kinetic energy of the jet on the cavity characteristics was analyzed.The findings reveal that the cavity profile exhibits a conical shape,primarily driven by direct jet impact and inertial effects.The expansion rates of both cavity length and maximum radius increase with jet impact kinetic energy.When the impact kinetic energy is reduced to 28.2 kJ or below,the length-to-diameter ratio of the cavity ultimately stabilizes at approximately 7.展开更多
Rammed earth possesses environmental advantages over most other competing construction materials.However,if it is to be more routinely used in the construction of modern,sustainable buildings,its material properties a...Rammed earth possesses environmental advantages over most other competing construction materials.However,if it is to be more routinely used in the construction of modern,sustainable buildings,its material properties and produc-tion processes must be properly quantified.This paper proposes practical recommendations for soil selection,stabilizer treatment,and on-site compaction for rammed earth,based on a recent set of 219 stabilization experiments.The pur-pose of the recommendations is to maximize the probability of constructing rammed earth walls that meet or exceed a compressive strength criterion of 2 MPa.The recommendations cover:(1)Quantifying the natural soil properties of linear shrinkage and texture in a staged sequence in order to identify suitable soils to stabilize(and to reject unsuit-able soils);(2)Quantifying the amounts of cement and/or lime to be added to the selected soil according to the values of soil properties measured;and(3)Quantifying the forces involved in on-site compaction of stabilized soil(for both manual and pneumatic ramming),and relating these to laboratory-based test standards.Although the recommenda-tions need to be tested and verified/refined using new data,their initial application to rammed earth construction situations in Australia indicates that they have predictive utility.Further research will also indicate the degree of applicability of the recommendations to the production of compressed earth bricks.展开更多
Past builders have developed very low-embodied energy construction techniques optimizing the use of local building materials.These techniques are a source of inspiration for modern sustainable building.Unfortunately,t...Past builders have developed very low-embodied energy construction techniques optimizing the use of local building materials.These techniques are a source of inspiration for modern sustainable building.Unfortunately,this know-how was orally transmitted and was lost as earth construction fell into disuse during the 20th century in European countries.The absence of written documents makes necessary to use an archaeological approach in order to rediscover these construction strategies.Micromorphological analysis of thin sections collacted in earth building walls was used for the first time to describe cob construction technique and highlighted several typical pedofeatures allowing to clearly identifying this process.Finally,a first comparison of the cob and rammed earth micromorphological features permitted to identify two key factors to distinguish these two techniques,the manufacturing state(solid or plastic)and the organization of the material in the wall.展开更多
Chinese watchtower houses are part of the unique human cultural heritage of the world’s vernacular architectures.Many earthen manor watchtower houses in Chongqing,China,have absorbed the characteristics of other towe...Chinese watchtower houses are part of the unique human cultural heritage of the world’s vernacular architectures.Many earthen manor watchtower houses in Chongqing,China,have absorbed the characteristics of other tower houses across the country and have brought together various types of watchtower construction techniques.They are important connection points for the integrity of the Chinese watchtower house as a comprehensive architectural cultural heritage system.They can be a typical sample of Chinese Han classical towers.These buildings are indispensable parts of the Chinese residential watchtower system and have important cultural protection value.However,due to the general lack of excavation and attention to their historical and cultural value,these buildings are on the verge of disappearing.Although they have lost their original architectural functions,they have important value in terms of their building materials,technical composition and artistic modelling.They can stimulate special emotional resonance and become an important bridge that maintains the cultural connection between ancient and modern humans.Therefore,discussing the historical and cultural value of Chongqing rammed earth watchtower houses,the strategy for heritage protection and utilisation is of far-reaching signifcance for Chinese watchtower dwellings.展开更多
Liquid-filled containers(LFC)are widely used to store and transport petroleum,chemical reagents,and other resources.As an important target of military strikes and terrorist bombings,LFC are vulnerable to blast waves a...Liquid-filled containers(LFC)are widely used to store and transport petroleum,chemical reagents,and other resources.As an important target of military strikes and terrorist bombings,LFC are vulnerable to blast waves and fragments.To explore the protective effect of polyurea elastomer on LFC,the damage characteristics of polyurea coated liquid-filled container(PLFC)under the combined loading of blast shock wave and fragments were studied experimentally.The microstructure of the polyurea layer was observed by scanning electron microscopy,and the fracture and self-healing phenomena were analyzed.The simulation approach was used to explain the combined blast-and fragments-induced on the PLFC in detail.Finally,the effects of shock wave and fragment alone and in combination on the damage of PLFC were comprehensively compared.Results showed that the polyurea reduces the perforation rate of the fragment to the LFC,and the self-healing phenomenon could also reduce the liquid loss rate inside the container.The polyurea reduces the degree of depression in the center of the LFC,resulting in a decrease in the distance between adjacent fragments penetrating the LFC,and an increase in the probability of transfixion and fracture between holes.Under the close-in blast,the detonation shock wave reached the LFC before the fragment.Polyurea does not all have an enhanced effect on the protection of LFC.The presence of internal water enhances the anti-blast performance of the container,and the hydrodynamic ram(HRAM)formed by the fragment impacting the water aggravated the plastic deformation of the container.The combined action has an enhancement effect on the deformation of the LFC.The depth of the container depression was 27%higher than that of the blast shock wave alone;thus,it cannot be simply summarized as linear superposition.展开更多
基金Supported by Fund for Scientific Research of Shaanxi University of Technology(SLG0811)~~
文摘Rammed earth wall technique is one of the local widespread traditional construction methods, and it has superior physical property and ecological protection characteristic. When contemporary raw-soil building is replaced by industry building, the hometown building culture is perishing gradually. In order to inherit and develop the Hanzhong local building, rammed earth wall in Taiyangling and Cangshe hometown is investigated, and the characteristics and construction techniques of the local rammed earth wall are concluded. According to the construction problems, the improvement suggestions are put forward, which establishes the foundation to investigate rammed earth wall further, and guide Rural House construction.
基金Supported by Fund of Key Scientific and Technological Project of Henan Province (10210210080)Henan Government Decision-making Research Bidding Project (2011B706)~~
文摘The scientific evaluation on heat insulation and preservation capacity of rammed earth construction can provide an effective evidence for its superiority in preserving thermal environment of the construction. By taking an eco-hotel in Zhejiang Anji County as the research object, 33 test points have been set. The indoor and outdoor air temperature of eco-hotel and the surface temperature of building envelopes had been recorded by using data acquisition instrument, temperature transmitter and other equipments from January 27 to February 2 in 2007. Then, the data of a period had been selected for comparison and analysis and the results had been obtained as follows. In January when the temperature difference between day and night in Anji was not large, without particular thermal insulation measures and equipments, the indoor temperature of eco-hotel fluctuated very little, showing that rammed earth construction was of obvious capacity for heat preservation and insulation, that its heat stability was evident and that it could ensure excellent indoor thermal environment.
文摘Based on the idea of optimization design of pile type, the two kinds of the typical pile type are selected, which containing flexibility pile (e.g. rammed cement-soil pile is for short RCSP), and rigid pile (e.g. cement-flyash-gravel pile is for short CFGP). The three kinds of the composite foundation are designed, which are CFGP, CFG long pile and CFG short pile (for short CFGLP-CFGSP), CFG long-short pile and rammed cement-soil short pile (for short CFGLP-RCSSP). Natural earthquake is simulated by using the engineering blasting;the dynamic characteristics and dynamic response of the composite foundation are studied through field test. CFGLP-RCSSP is closed to linear relation. The bearing capacity of the four composite foundation of the CFGP, CFGLP-CFGSP, and CFGLP-RCSSP in the site are 225 kPa, 179 kPa, and 197 kPa, separately increases 150%, 98.8% and 119% compared to the natural foundation. The vibration main frequency is mainly depended on properties of foundation soil and piles between vibration source and measuring point, pilling load value. Horizontal vibration main frequency greater than the vertical vibration main frequency and the vertical vibration main frequency close to the first-order natural frequency of composite foundation. With the pilling load increasing, the CFGLP-RCSSP pile composite foundation combined frequency decreased. Under the same blast energy, the acceleration peak on the CFG pile composite foundation is less than CFGLP-CFGSP the corresponding values, as the load increases, the peak acceleration gently. CFG pile composite foundation is favorable on seismic. The distribution of peak acceleration is consistent within 4 m from pile top in the CFGLP_RCSSP composite foundation. The maximum of the horizontal acceleration peak along the pile body occurs at a distance of pile top 4 m or the pile top, and that of vertical acceleration peak occurred at a pile top.
文摘The authors regret that in the paper of Baldovino et al.(2019),published in Journal of Rock Mechanics and Geotechnical Engineering(JRMGE),Eq.(2)must be corrected.Eq.(2)in the original paper describes a formula to calculate the unconfined compressive strength(q_u).But Authors wrote it as if it were the formula for calculating the split tensile strength(qt).To amend this error,Eq.(1)and Eq.(2)are the correct expressions for q_u and q_t measurements,respectively.
基金financial support from the National Natural Science Foundation of China(Grant No.11572159).
文摘The cavity characteristics in liquid-filled containers caused by high-velocity impacts represent an important area of research in hydrodynamic ram phenomena.The dynamic expansion of the cavity induces liquid pressure variations,potentially causing catastrophic damage to the container.Current studies mainly focus on non-deforming projectiles,such as fragments,with limited exploration of shaped charge jets.In this paper,a uniquely experimental system was designed to record cavity profiles in behind-armor liquid-filled containers subjected to shaped charge jet impacts.The impact process was then numerically reproduced using the explicit simulation program ANSYS LS-DYNA with the Structured Arbitrary Lagrangian-Eulerian(S-ALE)solver.The formation mechanism,along with the dimensional and shape evolution of the cavity was investigated.Additionally,the influence of the impact kinetic energy of the jet on the cavity characteristics was analyzed.The findings reveal that the cavity profile exhibits a conical shape,primarily driven by direct jet impact and inertial effects.The expansion rates of both cavity length and maximum radius increase with jet impact kinetic energy.When the impact kinetic energy is reduced to 28.2 kJ or below,the length-to-diameter ratio of the cavity ultimately stabilizes at approximately 7.
文摘Rammed earth possesses environmental advantages over most other competing construction materials.However,if it is to be more routinely used in the construction of modern,sustainable buildings,its material properties and produc-tion processes must be properly quantified.This paper proposes practical recommendations for soil selection,stabilizer treatment,and on-site compaction for rammed earth,based on a recent set of 219 stabilization experiments.The pur-pose of the recommendations is to maximize the probability of constructing rammed earth walls that meet or exceed a compressive strength criterion of 2 MPa.The recommendations cover:(1)Quantifying the natural soil properties of linear shrinkage and texture in a staged sequence in order to identify suitable soils to stabilize(and to reject unsuit-able soils);(2)Quantifying the amounts of cement and/or lime to be added to the selected soil according to the values of soil properties measured;and(3)Quantifying the forces involved in on-site compaction of stabilized soil(for both manual and pneumatic ramming),and relating these to laboratory-based test standards.Although the recommenda-tions need to be tested and verified/refined using new data,their initial application to rammed earth construction situations in Australia indicates that they have predictive utility.Further research will also indicate the degree of applicability of the recommendations to the production of compressed earth bricks.
基金The authors want to acknowledge Dr.Ashish Shukla of Coventry University for his kind proofreading of the manuscript.
文摘Past builders have developed very low-embodied energy construction techniques optimizing the use of local building materials.These techniques are a source of inspiration for modern sustainable building.Unfortunately,this know-how was orally transmitted and was lost as earth construction fell into disuse during the 20th century in European countries.The absence of written documents makes necessary to use an archaeological approach in order to rediscover these construction strategies.Micromorphological analysis of thin sections collacted in earth building walls was used for the first time to describe cob construction technique and highlighted several typical pedofeatures allowing to clearly identifying this process.Finally,a first comparison of the cob and rammed earth micromorphological features permitted to identify two key factors to distinguish these two techniques,the manufacturing state(solid or plastic)and the organization of the material in the wall.
基金Sichuan Fine Arts Insititute Doctoral Research Program‘Chongqing Bayu Watch Tower House Construction Art History and Culture Tracing and Application Research’(2018BSBY016)Chongqing Art Science Research Planning Project‘Study on collage protection strategy of architectural cultural heritage of endangered rammed earth blockhouses in Bayu’(21ZD04)。
文摘Chinese watchtower houses are part of the unique human cultural heritage of the world’s vernacular architectures.Many earthen manor watchtower houses in Chongqing,China,have absorbed the characteristics of other tower houses across the country and have brought together various types of watchtower construction techniques.They are important connection points for the integrity of the Chinese watchtower house as a comprehensive architectural cultural heritage system.They can be a typical sample of Chinese Han classical towers.These buildings are indispensable parts of the Chinese residential watchtower system and have important cultural protection value.However,due to the general lack of excavation and attention to their historical and cultural value,these buildings are on the verge of disappearing.Although they have lost their original architectural functions,they have important value in terms of their building materials,technical composition and artistic modelling.They can stimulate special emotional resonance and become an important bridge that maintains the cultural connection between ancient and modern humans.Therefore,discussing the historical and cultural value of Chongqing rammed earth watchtower houses,the strategy for heritage protection and utilisation is of far-reaching signifcance for Chinese watchtower dwellings.
基金supported by the National Natural Science Foundation of China(Grant Nos.12102480,52278543 and 51978660)Natural Science Foundation of Jiangsu Province(Grant No.BK20231489)。
文摘Liquid-filled containers(LFC)are widely used to store and transport petroleum,chemical reagents,and other resources.As an important target of military strikes and terrorist bombings,LFC are vulnerable to blast waves and fragments.To explore the protective effect of polyurea elastomer on LFC,the damage characteristics of polyurea coated liquid-filled container(PLFC)under the combined loading of blast shock wave and fragments were studied experimentally.The microstructure of the polyurea layer was observed by scanning electron microscopy,and the fracture and self-healing phenomena were analyzed.The simulation approach was used to explain the combined blast-and fragments-induced on the PLFC in detail.Finally,the effects of shock wave and fragment alone and in combination on the damage of PLFC were comprehensively compared.Results showed that the polyurea reduces the perforation rate of the fragment to the LFC,and the self-healing phenomenon could also reduce the liquid loss rate inside the container.The polyurea reduces the degree of depression in the center of the LFC,resulting in a decrease in the distance between adjacent fragments penetrating the LFC,and an increase in the probability of transfixion and fracture between holes.Under the close-in blast,the detonation shock wave reached the LFC before the fragment.Polyurea does not all have an enhanced effect on the protection of LFC.The presence of internal water enhances the anti-blast performance of the container,and the hydrodynamic ram(HRAM)formed by the fragment impacting the water aggravated the plastic deformation of the container.The combined action has an enhancement effect on the deformation of the LFC.The depth of the container depression was 27%higher than that of the blast shock wave alone;thus,it cannot be simply summarized as linear superposition.
