膨胀土边坡稳定性理论计算方法对比研究

Comparative Study on Theoretical Calculation Methods of Expansive Soil Slope Stability

膨胀土边坡是工程实践中经常遇到的一种特殊土质边坡,该边坡的土质具有良好的亲水性,主要表现为失水收缩、吸水膨胀的物理特性,这使得膨胀土边坡成为岩土工程界的热点研究课题。本文通过引入膨胀力来对膨胀土边坡进行受力分析,总结了Fellenius法、Bishop法、Morgenstern-Price法和Spencer法4种极限平衡法的计算原理,并结合国内某实际工程案例对4种方法分析讨论,对比在引入膨胀力前后边坡的安全系数,搜索计算膨胀土边坡的最危险滑动面和稳定性系数K值。研究结果表明:(1)采用Fellenius法对边坡的稳定性进行分析时边坡更偏于安全;(2)考虑膨胀力的作用对边坡的稳定性计算更加偏于安全;(3)边坡中膨胀土的膨胀力越大,在其浅表层发生滑坡的几率越大。

Expansive soil slope is a special soil slope frequently encountered in engineering practice. The soil of this slope has good hydrophilicity,which is mainly reflected by its physical characteristics of expanding in the presence of water and shrinking in the condition of water loss. This makes expansive soil slope a hot research topic in geotechnical engineering. This paper provides the stress analysis of the expansive soil slope by introducing expansive force,summarizes the calculation principles of four limit equilibrium methods,namely Fellenius method,Bishop method,Morgenstern-Price method and Spencer method,analyzes and discusses the four methods by combining a practical project case in China,compares the safety factors of the slope before and after the introduction of expansive force,and searches and calculates the most dangerous sliding surface and stability coefficient K of the expansive soil slope. The results show that:(1)The slope is safer when Fellenius method is used to analyze the stability of the slope.(2)The slope stability calculated is safer when the effect of expansive force is taken into consideration.(3)The slope is more likely to experience landslide in its shallow surface layer if the expansive soil in the slope has a larger expansive force.