Experimental Study on Stability Evaluation of Earth Slopes

在粘性土的模型试验中进行了滑动载荷试验，以检查滑动面的发展和相关的孔隙水压力。对于2.9m高的原型路堤边坡破坏，试验中观察到的滑动面多为通过坡脚的圆形滑动面，利用模型土样的总应力强度参数进行稳定性分析可以很好地解释这一现象。然而，模型中孔隙水压力的测量精度相对较差，无法结合填土的实际滑动和变形行为来讨论破坏机制。为了研究心墙自重变形规律，还对心墙居中布置的模型堆石坝进行了重力加载试验。两种不同类型岩心在岩心沟槽附近均出现了明显的应变集中现象， ...更多信息 采用非线性有限元应力分析方法，考虑分步布置条件，对变形量与抗滑安全系数之间的关系进行了研究。结果表明，安全系数与施工期侧向变形之间存在一定的相关性，虽然安全系数与施工期侧向变形之间的关系在定性上是肯定的，但有限元法得到的安全系数值与常规稳定分析方法得到的安全系数值并不完全一致。对降雨作用下的渗流问题进行了二维非稳定饱和-非饱和渗流有限元分析，研究了时间间隔、有限元网格尺寸和允许收敛误差对解的影响。指出了时间间隔与允许误差之间存在着唯一的关系，只有满足这些参数的解析条件，才能保证渗流问题的解的准确性。少

Centrifuge loading tests were carried out on model embankments of cohesive soils in order to examine development of sliding surfaces and associated pore water pressures in the fill. Concerning slope failures of 2.9m high prototype embankment, circular sliding surfaces passing through the toe of the slope were mostly observed in the test, which can well be explained in the stability analysis made by use of total stress strength parameters obtained on soil samples from the model. Measurement of pore water pressures in the model, however, was relatively poor in accuracy to discuss failure mechanism together with actual sliding and deformation behavior of the fill. Centrifuge loading tests were also conducted on model rockfill dams with a centrally located core to investigate deformation pattern of the core due to self-weight. Severe strain concentration was remarkably seen in the vicinity of core trench for two different types of the core tested, and deformation patterns of theses models … More were satisfactorily followed qualitatively by a simple gravity turn-on FE elastic stress analysis.The relationship between the magnitude of deformation and the safety factor against sliding was examined by use of a non-linear FE stress analysis method and by taking step-by-step placement condition into account. It is concluded that there should be a certain correlation between the value of safety factor and that of lateral deformation during construction, and that the value of safety factor obtained by FEM does not coincide closely with that of an ordinary method of stability analysis, though the relationship between the safety factor and the lateral deformation is qualitatively affirmative. Two dimensional unsteady saturated-unsaturated FE seepage analysis was also made on seepage flow through embankments by rainfall to study the influence of the time interval, size of FE mesh and the allowable error for convergence to the solutions. It is summarized that there is a unique relationship between the time interval and the allowable error to obtain a certain reliable solution and that analytical conditions on those parameters mentioned above should be sated plainly for the solutions of these seepage problems to present their credit in accuracy. Less