主应力轴旋转下高偏压固结粉土动力特性研究.docVIP

 主应力轴旋转下高偏压固结粉土动力特性 研究# 沈扬1,2，闫俊1,2，刘汉龙1,2，张健1,2* 5 10 15 20 25 30 35 （1. 河海大学岩土力学与堤坝工程教育部重点实验室，南京 210098； 2. 河海大学岩土工程科学研究所，南京 210098） 摘要：为了研究不同固结方式对粉土在波浪荷载引起的主应力轴循环旋转下的性状影响，对 长江入海口相对密实度为 70%的饱和粉土进行空心圆柱试验。结果表明主应力轴旋转下，固 结比为 1 的试样，随动剪应力增大，孔压开展由三阶段两相态点模式转化为二阶段单相态点 模式；而主应变差则在 0.2%－0.5%这一小应变范围内发生崩塌，并与孔压激变相态点基本 同步发生。固结比为 2 的试样，孔压开展仅有二阶段单相态点模式，且孔压比至 0.45 保持 稳定；主应变差则能平稳开展至较大幅值，比等向固结试样有更高动强度。最后采用修正 seed 模型及双曲线模型分别对等压及偏压固结试样的孔压开展进行预测，结果表明，模型 拟合效果良好，参数能反映剪应力水平对孔压开展的影响。 关键词：主应力轴旋转；固结比；粉土；孔压 中图分类号：TU435 Dynamic behaviors of anisotropically-consolidated silt under principal stress rotation SHEN Yang1,2, YAN Jun1,2, LIU Han long1,2, ZHANG Jian1,2 (1. Key Laboratory of Ministry of Education for Geomechanics and Embankment Engineering, Hohai University, NanJing 210098; 2. Institute of Geotechnical Engineering, Hohai University, NanJing 210098) Abstract: In order to assess the influcence of consolidation ratio(KC) on silt’s behaviors under cyclic principal stress rotation (CPSR) induced by wave loads, hollow cylinder samples experiments were conducted on remoulded Yangtze river silt with the relative density of 70%. The results showed that under CPSR as for the samples with KC=1, before failure the development of pore water pressure changed from two-phase transformation point three-stage mode into sinlge-phase transformation point two-stage mode with the increase of shear stress. As to the strain, the maximum deviator strain was limited within 0.2％to 0.5％ at the collapse points and occured basically simultaneously with the cataclysmic phase transformation point of pore water pressure. While KC=2, the pore water pressure belonged to sinlge-phase transformation point two-stage mode and its ratio remained stable at the value of around 0.45. As a result, the strain could generate smoothly to large extent and the samples had higher dynamic strength than the ones with KC=1. Eventually, the development of pore water pressure of the samples with KC =1 and 2 were respectively predicted