淤泥质土封闭作用下侧压力试验研究

天然软土上覆的硬壳层对其下的软土具有封闭作用,会改变其下软土层侧压力分布及传递规律。为探究封闭作用下淤泥质土侧向土压力特性,通过模拟3种不同工况的室内试验,研究含水率、加载方式、硬壳层完整性对侧压力竖向分布规律,侧压力系数及横向传递特性的影响。试验结果表明:侧向土压力沿深度呈上段抛物线、下段近似直线的半抛物线形分布,其半抛物线趋势受含水率、荷载等级的影响;侧压力系数在一定范围内随深度增加,之后趋于稳定,受含水率影响不大。该结果证明,封闭状态下淤泥质土侧向受荷性能具有类似流体的性质,从工程安全角度考虑,设计时可将封闭状态下淤泥质土侧压力系数取为1。同时,硬壳层完整性对淤泥土中应力传递具有一定影响。

Experimental Study on Lateral Pressure of Muddy Soil under Closure Effect

The crust layer above the natural soft soil has a closure effect on the soft soil underneath, which will change the distribution and transmission of lateral pressure in the soft soil layer. In order to explore the lateral soil pressure characteristics of the muddy soil under the closure effect, laboratory experiments by simulating three kinds of construction conditions are conducted to study the influence of water content, loading mode and crust layer integrity on the vertical distribution of the lateral pressure, the lateral pressure coefficient and the lateral transfer. The test results show that the lateral soil pressure tends to distribute in a semi-parabolic(the upper-parabolic and the lower-linear); the semi-parabolic trend is affected by the water content and load grade; the he lateral pressure coefficient increases with the depth within a certain range and then stabilizes with minor effect of water content, which indicate that the lateral loading behavior of the muddy soil in closed state is similar to that of the fluid. From the perspective of engineering safety, the lateral pressure coefficient of the muddy soil can be taken as 1 in the closed state. At the same time, the integrity of the crust layer has certain effect on the stress transfer in the muddy soil.