考虑各向异性的土压力离心模型试验研究

Centrifuge Model Tests on Active Earth Pressure Calculation Considering Strength Anisotropy of the Soils

挡土墙后填土通常具有一定的强度各向异性,但目前的土压力计算方法通常将其简化为各向同性材料。为揭示强度各向异性对主动土压力的影响规律及其机理,采用椭圆形截面的金属棒堆积形成二维粒状材料,并针对这种二维粒状材料研制了主动土压力的离心模型试验设备与测试技术。初步试验表明,墙后填土的强度各向异性对主动土压力沿墙高的分布规律有一定影响。随填土沉积面倾角增加,主动土压力的合力作用点逐渐向挡墙底部靠近。此外,墙后主动土压力受填土强度各向异性影响的程度可能达到40%。

Soil behind retaining walls usually behaves with anisotropic strength, while it is taken as an isotropic material in the current earth pressure calculations. In order to study the effect of strength anisotropy on active earth pressure, a centrifuge testing method together with the measuring technology was proposed in this paper. Soils with anisotropic strength were modeled with two-dimensional granular materials deposited by metal bars with elliptical cross section. Two centrifuge modeling tests were carried out on the same material with different deposition angles. It was shown that the distribution of active earth pressure was affected by deposition angle. The action point of active earth pressure moved gradually to the bottom of the wall when deposition angle increases. The maximum active earth pressure with vertical deposition surface could be 40 percent larger than that with horizontal deposition surface.