Experimental Study on Stability Evaluation of Earth Slopes

在粘性土模型路堤上进行了离心机加载试验，以考察滑动面的发展及其在填土中的相关孔压。对于2.9m高的原型路堤边坡的破坏，试验中观察到的主要是穿过坡趾的圆形滑动面，这在利用模型土样获得的总应力强度参数进行稳定性分析中得到了很好的解释。然而，模型中的孔压测量精度相对较低，无法结合填土的实际滑动和变形特性来讨论破坏机理。此外，还对具有中心心墙的模型堆石坝进行了离心机加载试验，以研究自重引起的心墙变形规律。对于两种不同类型的岩心，在岩心沟槽附近有明显的应变集中，这两种模型的变形模式为…通过简单的重力开启有限元弹性应力分析，研究了变形大小与抗滑安全系数之间的关系，并考虑了逐步放置条件。结果表明，在施工过程中安全系数与侧向变形值之间存在一定的相关性，虽然安全系数与侧向变形量之间的关系是定性的，但有限元计算得到的安全系数与一般稳定性分析方法得到的安全系数值并不十分吻合。对降雨作用下路堤渗流问题进行了二维非稳定饱和-非饱和有限元渗流分析，研究了时间间隔、有限元网格大小和收敛误差对计算结果的影响。总结出在时间间隔和允许误差之间存在唯一的关系，以获得一定的可靠解，并且应清楚地满足对上述参数的分析条件，以使这些渗流问题的解准确地展现其可信度。较少

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