长江口饱和软黏土多静力因子耦合响应规律

Coupling Response Characteristics of Multiple Static Factors of Saturated Soft Clay in the Yangtze River Estuary

以长江口长兴岛周边水域原状海相饱和软黏土为研究对象,通过GDS静三轴试验,探讨预压静荷载、加荷速率、排水条件等静力因子作用下软黏土固结不排水强度和孔压特性响应规律,以及预压堆载与加荷速率联合作用下软黏土固结不排水强度及孔压耦合响应模式。研究结果表明:随着堆载预压荷载的增大,软黏土总强度增大,但抗剪强度降低,同时孔隙水压力随之降低,应力-应变关系曲线向应变软化趋势发展;随着加荷速率的加快,孔压峰值减小,软黏土的强度有所提高,应力-应变关系曲线向应变硬化趋势发展;采用竖向排水板可提高固结排水速率,缩短软黏土固结时间,提高抗剪强度;采用归一化处理得到静偏应力比s1与加载速率ε/ε0,分别建立了静力因子耦合作用下关于s1及ε/ε0的强度峰值和孔压峰值表达式。

Taking the undisturbed marine saturated soft clay around Changxing Island in the Yangtze River estuary as the research object,with the GDS static triaxial test,the response law of consolidated undrained strength and pore pressure characteristics of soft clay under static factors such as preloaded static load,loading rate,and drainage conditions were studied.The coupled response model of consolidated undrained strength and pore pressure of soft clay under the combined action of preloading and loading rate were discussed.The results are as follows.Firstly,with the increase of the preloading load,the total strength of soft clay increases,but the shear strength decreases,and the pore water pressure decreases accordingly,and the stress-strain relationship curve will develop towards strain softening.Secondly,with the acceleration of loading rate,the peak value of pore pressure decreases,the strength of soft clay increases,and the stress-strain relationship curve will develop towards strain hardening.Thirdly,the use of vertical drainage plate can increase the consolidation drainage rate,shorten the consolidation time of soft clay,and improve the shear strength.Finally,with the data normalization method,the static deviatoric stress ratio and loading rate are obtained.The relationship expressions of strength peak value and pore pressure peak value of and under static factor coupling are established respectively.