When mining metal mines with steep structure planes by the caving method,there is a mechanical model in which the horizontal stress on the rock mass is simplified as a column before surface subsidence.The model is use...When mining metal mines with steep structure planes by the caving method,there is a mechanical model in which the horizontal stress on the rock mass is simplified as a column before surface subsidence.The model is used to deduce critical support load and limiting column length for a given horizontal stress and support pressure.Considering the impact of the column effect,a method is proposed to determine the movement of the ground and caving area in a mine.After surface subsidence,the horizontal stress on a surrounding rock mass can be simplified to a cantilever beam mechanical model.Expressions for its bending fracture length are deduced,and a method is given to determine its stability.On this basis,an explanation for the large ground movement and subsidence scope was given.A case study shows that the damage effect of column and cantilever beam is significant for ground movement in metal-ore mine,and an appropriate correction value should be applied when designing for its angle of ground movements.展开更多
This paper proposes an optimization model for the airport ground movement problem(GMP)based on bilevel programming to address taxi conflicts on the airport ground and to improve the operating safety and efficiency.To ...This paper proposes an optimization model for the airport ground movement problem(GMP)based on bilevel programming to address taxi conflicts on the airport ground and to improve the operating safety and efficiency.To solve GMP,an iterative heuristic algorithm is designed.Instead of separately investigating each problem,this model simultaneously coordinates and optimizes the aircraft routing and scheduling.A simulation test is conducted on Nanjing Lukou International Airport(NKG)and the results show that the bilevel programming model can clearly outperform the widely used first-come-first-service(FCFS)scheduling scheme in terms of aircraft operational time under the precondition of none conflict.The research effort demonstrates that with the reduced operating cost and the improved overall efficiency,the proposed model can assist operations of the airports that are facing increasing traffic demand and working at almost maximum capacity.展开更多
This study tried to explore the ground movement induced by triple stacked tunneling(TST) with different construction sequences. A case study in Tianjin, China was used to investigate the ground movement during the TST...This study tried to explore the ground movement induced by triple stacked tunneling(TST) with different construction sequences. A case study in Tianjin, China was used to investigate the ground movement during the TST(upper tunneling(UT)). For this, a modified Peck formula was proposed to predict the surface settlement induced by TST. Next, three sets of finite element analyses(FEA) were used to compare the effects of construction sequences(i.e. UT, middle tunneling(MT), and lower tunneling(LT)) on vertical and lateral ground displacements. The results of Tianjin case and UT reveal that compared to a Gaussian distribution for a single tunnel, the surface settlement curve of triple stacked tunnels is a bimodal distribution. It seems that the proposed modified Peck formula can effectively predict the surface settlement induced by TST. The results of the three sets of FEA demonstrate that the construction sequence has a significant influence on the ground movement. Among the three construction sequences, the largest lateral displacement is observed in the MT and the smallest one in UT.The existing tunnel has an inhibitory effect on the vertical displacement. The maximum value of the lateral displacement occurs at the depth of the new tunnel in each construction sequence.展开更多
To trace the potential hazards of open-pit slope in Longshou mine,global positioning system（GPS） is applied to monitoring ground movement and deformation induced by transition from open-pit to underground mining.Thr...To trace the potential hazards of open-pit slope in Longshou mine,global positioning system（GPS） is applied to monitoring ground movement and deformation induced by transition from open-pit to underground mining.Through long-term monitoring from 2003 to 2008,huge amounts of data were acquired.Monitoring results show that large-scale ground movement and deformation have occurred in mining area,and the movement area is ellipse-shaped.The displacement boundary of settlement trough is 2.0 km long along the exploratory line,and 1.5 km long along the strike of ore body.GPS monitoring results basically agree with the practical deformation state of open-pit slope.It is indicated that the long-term GPS monitoring is an effective way to understand the mechanism of ground movement and deformation in mine area. 更多展开更多
The strata movement induced by sub-critical extraction is a problem not receiving due attention because of its relatively small magnitude of deformation.However,with the increase of mining depth,sub-critical extractio...The strata movement induced by sub-critical extraction is a problem not receiving due attention because of its relatively small magnitude of deformation.However,with the increase of mining depth,sub-critical extraction has become a general phenomenon.This calls for an in-depth investigation into the characteristics of ground movements observed under different extents of sub-critical extraction,so as to determine the appropriate mining technique for use.Following a discussion of the factors influencing the extent of super-critical extraction,the super-critical extraction extent evaluation criteria was presented,the characteristics and laws of the strata and ground movements caused by such an extraction condition were systematically analyzed,and the mechanism of surface subsidence induced by sub-critical extraction was revealed.The result of study may serve as a basis for the development of the strata and ground movement prediction model and the mining techniques appropriate for use at depth beneath surface structures and buildings.展开更多
Based on Darcy Gersevanov law concerning a flow relation between water and solids, we derive the horizontal movement of solid frame resulted from a discharging well in a Theis Thiem confined system, and further anal...Based on Darcy Gersevanov law concerning a flow relation between water and solids, we derive the horizontal movement of solid frame resulted from a discharging well in a Theis Thiem confined system, and further analyze the relations among the horizontal movements and pumped time t as well as radius r from the discharging well. As applications of the theory, we propose some new interperations for ground fissure activity and casing failures induced by groundwater withdrawal or injection.展开更多
This paper considers the processes of activation in ground subsidence movements in flooding mine workings of mines being liquidated in two districts in Donetsk city on the area of more than 60km^2. A concept is give...This paper considers the processes of activation in ground subsidence movements in flooding mine workings of mines being liquidated in two districts in Donetsk city on the area of more than 60km^2. A concept is given to build up control network of geomechanical monitoring in conditions of existing old mining operations at shallow depths (down to 100m), strong damages of objects of urban building. Given are GPS network structure, layouts for location of basic and local profile lines, special control stations for monitoring ground subsidence movements over the territory of mines being flooded. Results of the series of observations made are discussed and their accuracy is analyzed.展开更多
Damage caused by underground coal mining is a serious problem in mining areas in China; therefore, studying and obtaining the rules of ground movement and deformation under different geological conditions is of great ...Damage caused by underground coal mining is a serious problem in mining areas in China; therefore, studying and obtaining the rules of ground movement and deformation under different geological conditions is of great importance. The numerical software ANSYS was used in this study to simulate mining processes under two special geological conditions： （1） thick unconsolidated soil layer and thin bedrock; （2） thin soil layer and thick bedrock. The rules for ground movement and deformation for different soil layer to bedrock ratios were obtained. On the basis of these rules, a prediction parameter modified model of the influence function was proposed, which is suitable for different values of unconsolidated soil layer thickness. The prediction results were verified using two sets of typical field data.展开更多
Patterns of ground movement and pore water pressure variation are obtained through a case study using a finite element method. With the progress of excavation, ground subsidence, ground inclination and horizontal disp...Patterns of ground movement and pore water pressure variation are obtained through a case study using a finite element method. With the progress of excavation, ground subsidence, ground inclination and horizontal displacement accelerates. Along the striking direction, a subsidence basin is formed on the ground surface induced by underground mining. The maximum subsidence is around 5.41m. The ratio of ground subsidence to the thickness of the coal seam is 1.08. The maximum inclination is 11.5 mm/m. The maximum horizontal displacement is 2.15 mm/m. At the time the coal has been excavated, the maximum pore water pressure reaches 25 kPa. In order to improve protection of structures lo- cated over the area with underground mining, the variation of additional stresses of a railway bridge induced by ground surface deformation is analyzed. The main effect of underground mining on the railway bridge is the tensile stress and the maximum value reaches as high as 4.29 MPa, which is greater than the concrete tensile strength.展开更多
In this study, a new method for quantitative and efficient measurement for the ground surface movement was developed. The feature of this technique is to identify geomorphic characteristics by image matching analysis,...In this study, a new method for quantitative and efficient measurement for the ground surface movement was developed. The feature of this technique is to identify geomorphic characteristics by image matching analysis, using the intelligent images made from high resolution DEM(Digital Elevation Model). This method is useful to extract the small ground displacement where the surface shape was not intensely deformed.展开更多
Abutment piles in soft ground may be subjected to both vertical and horizontal soil movements resulting from approach embankment loads. To constrain the soil movements, the soft soil ground beneath the approach embank...Abutment piles in soft ground may be subjected to both vertical and horizontal soil movements resulting from approach embankment loads. To constrain the soil movements, the soft soil ground beneath the approach embankment is often improved using composite pile foundations, which aim at mitigating the bump induced by high-speed trains passing through the bridge. So far, there is limited literature on exploring the influence of the degree of ground improvement on abutment piles installed in soft soil grounds. In this paper, a series of three-dimensional （3D） centrifuge model tests was performed on an approach embankment over a silty clay deposit improved by cement-fly ash-gravel （CFG） piles combined with geogrid. Emphasis is placed on the effects of ground replacement ratio （m） on the responses of the abutment piles induced by embankment loads. Meanwhile, a numerical study was conducted with varying ground replacement ratio of the pile-reinforced grounds. Results show that the performance of the abutment piles is significantly improved when reinforcing the ground with CFG piles beneath the approach embankment. Interestingly, there is a threshold value of the replacement ratio of around 4.9% above which the effect of CFG pile foundations is limited. This implies that it is essential to optimize the ground improvement for having a cost-effective design while minimizing the risk of the bump at the end of bridge.展开更多
To date, many studies related to robots have been performed around the world. Many of these studies have assumed operation at locations where entry is difficult, such as disaster sites, and have focused on various ter...To date, many studies related to robots have been performed around the world. Many of these studies have assumed operation at locations where entry is difficult, such as disaster sites, and have focused on various terrestrial robots, such as snake-like, humanoid, spider-type, and wheeled units. Another area of active research in recent years has been aerial robots with small helicopters for operation indoors and outdoors. However,less research has been performed on robots that operate both on the ground and in the air. Accordingly, in this paper, we propose a hybrid aerial/terrestrial robot system. The proposed robot system was developed by equipping a quadcopter with a mechanism for ground movement. It does not use power dedicated to ground movement, and instead uses the flight mechanism of the quadcopter to achieve ground movement as well. Furthermore, we addressed the issue of obstacle avoidance as part of studies on autonomous control. Thus, we found that autonomous control of ground movement and flight was possible for the hybrid aerial/terrestrial robot system, as was autonomous obstacle avoidance by flight when an obstacle appeared during ground movement.展开更多
The complex behaviors of expansive soils,particularly their volumetric changes driven by moisture variations,pose significant challenges in urban geotechnical engineering.Although vegetation-induced moisture changes a...The complex behaviors of expansive soils,particularly their volumetric changes driven by moisture variations,pose significant challenges in urban geotechnical engineering.Although vegetation-induced moisture changes are known to affect ground movement,quantitative characterization of tree–soil interactions remains limited due to insufficient field data and unclear relationships between tree water uptake and soil response.This study investigates the mechanical behavior of expansive clay soils influenced by two Lophostemon confertus samples during a 14-month field monitoring program in Melbourne,Australia.The research methodology integrates measurements of soil displacement,total soil suction,moisture content,and tree water consumption through instrumentation and monitoring systems.Field measurements suggest that tree roots reached the limits of their water extraction capacity when total soil suction exceeded 2880 kPa within the active root zone.The spatial extent of tree-induced soil desiccation reached 0.6–0.7 times the tree height laterally and penetrated to depths of 2.5–3.3 m vertically.The mature sample,with an 86%greater crown area and a threefold larger sapwood area,exhibited 142%higher water consumption(35 kL),demonstrating the scalability of tree–soil interaction mechanisms.A multiple linear regression model was developed to quantify the coupled relationships between soil movement and key variables,achieving a high adjusted R2 value of 0.97,which provides engineers and practitioners with a practical tool for estimating ground movement near trees.These findings offer valuable insights for infrastructure design in tree-adjacent environments and can inform computational models and design codes to enable more accurate site assessments and sustainable urban development.展开更多
基金Project(51274188)supported by the National Natural Science Foundation of China
文摘When mining metal mines with steep structure planes by the caving method,there is a mechanical model in which the horizontal stress on the rock mass is simplified as a column before surface subsidence.The model is used to deduce critical support load and limiting column length for a given horizontal stress and support pressure.Considering the impact of the column effect,a method is proposed to determine the movement of the ground and caving area in a mine.After surface subsidence,the horizontal stress on a surrounding rock mass can be simplified to a cantilever beam mechanical model.Expressions for its bending fracture length are deduced,and a method is given to determine its stability.On this basis,an explanation for the large ground movement and subsidence scope was given.A case study shows that the damage effect of column and cantilever beam is significant for ground movement in metal-ore mine,and an appropriate correction value should be applied when designing for its angle of ground movements.
基金supported by the National Natural Science Foundations of China(Nos.U1933118,U2033205)。
文摘This paper proposes an optimization model for the airport ground movement problem(GMP)based on bilevel programming to address taxi conflicts on the airport ground and to improve the operating safety and efficiency.To solve GMP,an iterative heuristic algorithm is designed.Instead of separately investigating each problem,this model simultaneously coordinates and optimizes the aircraft routing and scheduling.A simulation test is conducted on Nanjing Lukou International Airport(NKG)and the results show that the bilevel programming model can clearly outperform the widely used first-come-first-service(FCFS)scheduling scheme in terms of aircraft operational time under the precondition of none conflict.The research effort demonstrates that with the reduced operating cost and the improved overall efficiency,the proposed model can assist operations of the airports that are facing increasing traffic demand and working at almost maximum capacity.
基金financially supported by the Open Project of the State Key Laboratory of Disaster Reduction in Civil Engineering (Grant No. SLDRCE17-01)the National Key Research and Development Program of China (Grant No.2017YFC0805402)the National Natural Science Foundation of China (Grant No. 51808387)。
文摘This study tried to explore the ground movement induced by triple stacked tunneling(TST) with different construction sequences. A case study in Tianjin, China was used to investigate the ground movement during the TST(upper tunneling(UT)). For this, a modified Peck formula was proposed to predict the surface settlement induced by TST. Next, three sets of finite element analyses(FEA) were used to compare the effects of construction sequences(i.e. UT, middle tunneling(MT), and lower tunneling(LT)) on vertical and lateral ground displacements. The results of Tianjin case and UT reveal that compared to a Gaussian distribution for a single tunnel, the surface settlement curve of triple stacked tunnels is a bimodal distribution. It seems that the proposed modified Peck formula can effectively predict the surface settlement induced by TST. The results of the three sets of FEA demonstrate that the construction sequence has a significant influence on the ground movement. Among the three construction sequences, the largest lateral displacement is observed in the MT and the smallest one in UT.The existing tunnel has an inhibitory effect on the vertical displacement. The maximum value of the lateral displacement occurs at the depth of the new tunnel in each construction sequence.
基金Supported by the National Natural Science Foundation of China (40972197,41002107, 41030750)the Program of Knowledge Innovation of the Chinese Academy of Sciences (KZCX2-YW-Q03-02)
文摘To trace the potential hazards of open-pit slope in Longshou mine,global positioning system（GPS） is applied to monitoring ground movement and deformation induced by transition from open-pit to underground mining.Through long-term monitoring from 2003 to 2008,huge amounts of data were acquired.Monitoring results show that large-scale ground movement and deformation have occurred in mining area,and the movement area is ellipse-shaped.The displacement boundary of settlement trough is 2.0 km long along the exploratory line,and 1.5 km long along the strike of ore body.GPS monitoring results basically agree with the practical deformation state of open-pit slope.It is indicated that the long-term GPS monitoring is an effective way to understand the mechanism of ground movement and deformation in mine area. 更多
基金Project supported by Doctoral Study Courses Foundation and Post-Doctoral Scientific Foundation.
文摘The strata movement induced by sub-critical extraction is a problem not receiving due attention because of its relatively small magnitude of deformation.However,with the increase of mining depth,sub-critical extraction has become a general phenomenon.This calls for an in-depth investigation into the characteristics of ground movements observed under different extents of sub-critical extraction,so as to determine the appropriate mining technique for use.Following a discussion of the factors influencing the extent of super-critical extraction,the super-critical extraction extent evaluation criteria was presented,the characteristics and laws of the strata and ground movements caused by such an extraction condition were systematically analyzed,and the mechanism of surface subsidence induced by sub-critical extraction was revealed.The result of study may serve as a basis for the development of the strata and ground movement prediction model and the mining techniques appropriate for use at depth beneath surface structures and buildings.
文摘Based on Darcy Gersevanov law concerning a flow relation between water and solids, we derive the horizontal movement of solid frame resulted from a discharging well in a Theis Thiem confined system, and further analyze the relations among the horizontal movements and pumped time t as well as radius r from the discharging well. As applications of the theory, we propose some new interperations for ground fissure activity and casing failures induced by groundwater withdrawal or injection.
文摘This paper considers the processes of activation in ground subsidence movements in flooding mine workings of mines being liquidated in two districts in Donetsk city on the area of more than 60km^2. A concept is given to build up control network of geomechanical monitoring in conditions of existing old mining operations at shallow depths (down to 100m), strong damages of objects of urban building. Given are GPS network structure, layouts for location of basic and local profile lines, special control stations for monitoring ground subsidence movements over the territory of mines being flooded. Results of the series of observations made are discussed and their accuracy is analyzed.
文摘Damage caused by underground coal mining is a serious problem in mining areas in China; therefore, studying and obtaining the rules of ground movement and deformation under different geological conditions is of great importance. The numerical software ANSYS was used in this study to simulate mining processes under two special geological conditions： （1） thick unconsolidated soil layer and thin bedrock; （2） thin soil layer and thick bedrock. The rules for ground movement and deformation for different soil layer to bedrock ratios were obtained. On the basis of these rules, a prediction parameter modified model of the influence function was proposed, which is suitable for different values of unconsolidated soil layer thickness. The prediction results were verified using two sets of typical field data.
基金Project 50574088 supported by the Nation Natural Science Foundation of China
文摘Patterns of ground movement and pore water pressure variation are obtained through a case study using a finite element method. With the progress of excavation, ground subsidence, ground inclination and horizontal displacement accelerates. Along the striking direction, a subsidence basin is formed on the ground surface induced by underground mining. The maximum subsidence is around 5.41m. The ratio of ground subsidence to the thickness of the coal seam is 1.08. The maximum inclination is 11.5 mm/m. The maximum horizontal displacement is 2.15 mm/m. At the time the coal has been excavated, the maximum pore water pressure reaches 25 kPa. In order to improve protection of structures lo- cated over the area with underground mining, the variation of additional stresses of a railway bridge induced by ground surface deformation is analyzed. The main effect of underground mining on the railway bridge is the tensile stress and the maximum value reaches as high as 4.29 MPa, which is greater than the concrete tensile strength.
文摘In this study, a new method for quantitative and efficient measurement for the ground surface movement was developed. The feature of this technique is to identify geomorphic characteristics by image matching analysis, using the intelligent images made from high resolution DEM(Digital Elevation Model). This method is useful to extract the small ground displacement where the surface shape was not intensely deformed.
基金funded by the Science and Technology Department of Railway Ministry (Grant No. Z2012061)
文摘Abutment piles in soft ground may be subjected to both vertical and horizontal soil movements resulting from approach embankment loads. To constrain the soil movements, the soft soil ground beneath the approach embankment is often improved using composite pile foundations, which aim at mitigating the bump induced by high-speed trains passing through the bridge. So far, there is limited literature on exploring the influence of the degree of ground improvement on abutment piles installed in soft soil grounds. In this paper, a series of three-dimensional （3D） centrifuge model tests was performed on an approach embankment over a silty clay deposit improved by cement-fly ash-gravel （CFG） piles combined with geogrid. Emphasis is placed on the effects of ground replacement ratio （m） on the responses of the abutment piles induced by embankment loads. Meanwhile, a numerical study was conducted with varying ground replacement ratio of the pile-reinforced grounds. Results show that the performance of the abutment piles is significantly improved when reinforcing the ground with CFG piles beneath the approach embankment. Interestingly, there is a threshold value of the replacement ratio of around 4.9% above which the effect of CFG pile foundations is limited. This implies that it is essential to optimize the ground improvement for having a cost-effective design while minimizing the risk of the bump at the end of bridge.
文摘To date, many studies related to robots have been performed around the world. Many of these studies have assumed operation at locations where entry is difficult, such as disaster sites, and have focused on various terrestrial robots, such as snake-like, humanoid, spider-type, and wheeled units. Another area of active research in recent years has been aerial robots with small helicopters for operation indoors and outdoors. However,less research has been performed on robots that operate both on the ground and in the air. Accordingly, in this paper, we propose a hybrid aerial/terrestrial robot system. The proposed robot system was developed by equipping a quadcopter with a mechanism for ground movement. It does not use power dedicated to ground movement, and instead uses the flight mechanism of the quadcopter to achieve ground movement as well. Furthermore, we addressed the issue of obstacle avoidance as part of studies on autonomous control. Thus, we found that autonomous control of ground movement and flight was possible for the hybrid aerial/terrestrial robot system, as was autonomous obstacle avoidance by flight when an obstacle appeared during ground movement.
基金funded by the Australian Research Council via the ARC Linkage(Grant No.LP16160100649).
文摘The complex behaviors of expansive soils,particularly their volumetric changes driven by moisture variations,pose significant challenges in urban geotechnical engineering.Although vegetation-induced moisture changes are known to affect ground movement,quantitative characterization of tree–soil interactions remains limited due to insufficient field data and unclear relationships between tree water uptake and soil response.This study investigates the mechanical behavior of expansive clay soils influenced by two Lophostemon confertus samples during a 14-month field monitoring program in Melbourne,Australia.The research methodology integrates measurements of soil displacement,total soil suction,moisture content,and tree water consumption through instrumentation and monitoring systems.Field measurements suggest that tree roots reached the limits of their water extraction capacity when total soil suction exceeded 2880 kPa within the active root zone.The spatial extent of tree-induced soil desiccation reached 0.6–0.7 times the tree height laterally and penetrated to depths of 2.5–3.3 m vertically.The mature sample,with an 86%greater crown area and a threefold larger sapwood area,exhibited 142%higher water consumption(35 kL),demonstrating the scalability of tree–soil interaction mechanisms.A multiple linear regression model was developed to quantify the coupled relationships between soil movement and key variables,achieving a high adjusted R2 value of 0.97,which provides engineers and practitioners with a practical tool for estimating ground movement near trees.These findings offer valuable insights for infrastructure design in tree-adjacent environments and can inform computational models and design codes to enable more accurate site assessments and sustainable urban development.
