Sand-gravel soil may not be suitable for structure use or excavation use as a result of their permeability and low-intensity.It may cause serious damage to the upper part of the structure for its considerable stress.H...Sand-gravel soil may not be suitable for structure use or excavation use as a result of their permeability and low-intensity.It may cause serious damage to the upper part of the structure for its considerable stress.How to assess and control the deformation of the ground is the main purpose of the soil reinforcement technology.Grouting is a method commonly used to meet those requirements.This study is designed to investigate the effects on shield construction in the sand-gravel stratum.展开更多
The settlement curve of the foundation endured the ramp load is an S-type curve,which is usually simulated via Poisson curve.Aimed at the difficulty of preferences in Poisson curve,an immune algorithm (IA) is used.IA ...The settlement curve of the foundation endured the ramp load is an S-type curve,which is usually simulated via Poisson curve.Aimed at the difficulty of preferences in Poisson curve,an immune algorithm (IA) is used.IA is able to obtain a multiple quasi-optimum solution while maintaining the population diversity.In this paper,IA is used in an attempt to obtain accurate settlement prediction.The predicted settlements obtained by IA are compared with those predicted by the least squares fitting method (LSM),the Asaoka method and the genetic algorithm (GA).The results show that IA is a useful technique for predicting the settlement of foundations with an acceptable degree of accuracy and has much better performance than GA and the Asaoka methods.展开更多
City metro tunnels are usually constructed as twin-parallel tunnels and their adjacent construction may lead to surface deformation,affecting the surface environment and the safety of the tunnels.Due to its strong dis...City metro tunnels are usually constructed as twin-parallel tunnels and their adjacent construction may lead to surface deformation,affecting the surface environment and the safety of the tunnels.Due to its strong dispersion,sandy cobble strata can be easily disturbed by shield tunneling.Based on the project of the Chengdu Metro Line 1,field and model tests were carried out to study the surface settlement caused by shield tunneling in sandy cobble strata by measuring surface settlement curves,ground loss ratios and construction influence zones.The discrete element method(DEM) was used to study the factors affecting the formation of ground arches in sandy cobble strata at the microscopic level.Results show that the shape of the surface settlement curve in sandy cobble strata is different from that in soft soil.The buried depth and clear spacing of the two tunnels had a significant impact on the formation of ground arches.展开更多
文摘Sand-gravel soil may not be suitable for structure use or excavation use as a result of their permeability and low-intensity.It may cause serious damage to the upper part of the structure for its considerable stress.How to assess and control the deformation of the ground is the main purpose of the soil reinforcement technology.Grouting is a method commonly used to meet those requirements.This study is designed to investigate the effects on shield construction in the sand-gravel stratum.
基金Project(No.NCET-06-0649)supported by the New Century Excel-lent Talents in University,China
文摘The settlement curve of the foundation endured the ramp load is an S-type curve,which is usually simulated via Poisson curve.Aimed at the difficulty of preferences in Poisson curve,an immune algorithm (IA) is used.IA is able to obtain a multiple quasi-optimum solution while maintaining the population diversity.In this paper,IA is used in an attempt to obtain accurate settlement prediction.The predicted settlements obtained by IA are compared with those predicted by the least squares fitting method (LSM),the Asaoka method and the genetic algorithm (GA).The results show that IA is a useful technique for predicting the settlement of foundations with an acceptable degree of accuracy and has much better performance than GA and the Asaoka methods.
基金Project supported by the National Basic Research (973) Program of China (No. 2010CB732105)the National Natural Science Foundation of China (Nos. 50908193,50925830,and 51208432)
文摘City metro tunnels are usually constructed as twin-parallel tunnels and their adjacent construction may lead to surface deformation,affecting the surface environment and the safety of the tunnels.Due to its strong dispersion,sandy cobble strata can be easily disturbed by shield tunneling.Based on the project of the Chengdu Metro Line 1,field and model tests were carried out to study the surface settlement caused by shield tunneling in sandy cobble strata by measuring surface settlement curves,ground loss ratios and construction influence zones.The discrete element method(DEM) was used to study the factors affecting the formation of ground arches in sandy cobble strata at the microscopic level.Results show that the shape of the surface settlement curve in sandy cobble strata is different from that in soft soil.The buried depth and clear spacing of the two tunnels had a significant impact on the formation of ground arches.
