Water content,dry density,void ratio,depth of soil layer,and seismic loading may all exert influence on the seismic subsidence of loess.Many scholars have carried out seismic subsidence tests of loess to simulate the ...Water content,dry density,void ratio,depth of soil layer,and seismic loading may all exert influence on the seismic subsidence of loess.Many scholars have carried out seismic subsidence tests of loess to simulate the stress on soil using unidirectional(axial)vibration instead of bidirectional vibration.We conduct seismic subsidence tests of loess using two different dynamic stress loading methods,unidirectional and bidirectional dynamic stress.In addition,the effects of different dynamic stress loading modes on the development of seismic subsidence of loess are compared for a case-study in northwestern China.The results show that(1)the increasing ratio of radial stress to axial stress has exerted significant influence on the seismic subsidence coefficient of loess under the loading mode of bidirectional dynamic stress(2)there is a critical ratio of radial stress to axial stress for seismic subsidence of loess,ranging from 0.6 to 0.8;when the ratio of radial load to axial load is greater than the critical value,the effect of bidirectional load on the development of seismic subsidence is more remarkable(3)when the ratio of radial load to axial load is smaller,the seismic subsidence of loess calculated by the existing unidirectional stress loading method is safe for engineering projects.However,if the value exceeds the safety ratio range it is dangerous to conduct safety evaluations using the seismic loess subsidence.The prediction value of seismic subsidence at engineering sites directly affects the later foundation treatment and the safety of the overlying structures.The seismic subsidence calculation and evaluation method in this study may provide a scientific basis for safety evaluations of loess sites in northwestern China.展开更多
基金sponsored by the open foundation for Key Laboratory of Loess Seismic Engineering of China Earthquake Administration(KLLEE-17-001)Basic Scientific Research Operating Expenses of the China Earthquake Administration(2018IESLZ08)+2 种基金Spark Program of China Earthquake Administration(XH20058Y)Key Research and Develop-ment Program of Gansu Province(18YF1FA101)the National Nat-ural Science Foundation of China(U1939209,51578518&51778590).
文摘Water content,dry density,void ratio,depth of soil layer,and seismic loading may all exert influence on the seismic subsidence of loess.Many scholars have carried out seismic subsidence tests of loess to simulate the stress on soil using unidirectional(axial)vibration instead of bidirectional vibration.We conduct seismic subsidence tests of loess using two different dynamic stress loading methods,unidirectional and bidirectional dynamic stress.In addition,the effects of different dynamic stress loading modes on the development of seismic subsidence of loess are compared for a case-study in northwestern China.The results show that(1)the increasing ratio of radial stress to axial stress has exerted significant influence on the seismic subsidence coefficient of loess under the loading mode of bidirectional dynamic stress(2)there is a critical ratio of radial stress to axial stress for seismic subsidence of loess,ranging from 0.6 to 0.8;when the ratio of radial load to axial load is greater than the critical value,the effect of bidirectional load on the development of seismic subsidence is more remarkable(3)when the ratio of radial load to axial load is smaller,the seismic subsidence of loess calculated by the existing unidirectional stress loading method is safe for engineering projects.However,if the value exceeds the safety ratio range it is dangerous to conduct safety evaluations using the seismic loess subsidence.The prediction value of seismic subsidence at engineering sites directly affects the later foundation treatment and the safety of the overlying structures.The seismic subsidence calculation and evaluation method in this study may provide a scientific basis for safety evaluations of loess sites in northwestern China.
