摘要
假设理想条件下的倾斜滑移面,根据路堤底部产生的相对位移下的土工格栅膜效应,利用莫尔圆推导出在土工格栅不同挠曲变形时土体中剪应力的计算公式,根据应力平衡条件得到路堤土的应力–应变状态。这种剪应力没有达到屈服状态时路堤土中应力调整即应力重分布现象称为"不完全土拱效应"。同时,设计以水袋泄水模拟路堤底部产生差异沉降的大型模型试验,分别监测路堤特定位置处的沉降、静止土压力以及铺设的土工格栅的轴向拉应变,代入模型计算并且与现有的几种设计理论比较。结果显示:Terzaghi方法与Handy方法的应力计算都不考虑差异沉降的过程,由于对侧向应力系数的定义不同,前者的竖向应力结果偏小而后者偏大;对于土工格栅的轴向拉应变,Giroud方法计算值偏向于保守,虽然Esponiza方法与实测结果比较接近,但是考虑到长期安全性以及土工材料的耐久性,采用本文的计算方法是比较合理的。
The mechanism of geosynthetic membrane effect is analyzed by utilizing geometrical and mechanical method,and the stress state of the embankment within the subsidence cupboard is deduced based on an assumption of an idealized slanted sliding surface,and the development of the shearing stress along the sliding surface is considered in the coefficient of active lateral earth pressure.The membrane effect and stress-strain state are coupled in the proposed calculation model.Then,a physical model test was performed to monitor the settlement and induced axial tensile strains of reinforcements,and the earth pressure,etc.A comparison of the test results to the proposed calculation model and several traditional design methods demonstrates that：the proposed method results are more close to the test results,which can take good care of the varying process of relative displacement and realistic slanted sliding surface.Because of different definitions of coefficient of lateral earth pressures,the vertical stress calculated from Terzaghi s method is small while that from Handy s method is large;For the strain of geosynthetic,the Giroud s method is considered to be too conservative and the Esponiza s is a little small,and the strain calculated from the proposed method is a little large,but it is reasonable when considering the serviceability and long-term creep of the geosynthetic.
出处
《岩石力学与工程学报》
EI
CAS
CSCD
北大核心
2012年第3期632-639,共8页
Chinese Journal of Rock Mechanics and Engineering
基金
国家自然科学基金资助项目(50878051)
关键词
土力学
土工格栅
不完全土拱效应
差异沉降
斜滑移面
膜效应
soil mechanics
geogrid
partially developed soil arch effect
differential settlement
inclined sliding surface
membrane effect
