边坡滑面正应力构成及分布模式选择

通过假定滑面的正应力分布来计算边坡安全系数，这是近年来极限平衡理论研究的一个突破，讨论滑面正应力的组成及合理假设模式对获得可靠、可信的安全系数具有重要意义。根据土条的力平衡条件得到滑面正应力是由滑体体积力（含坡面外力）和土条间作用力这两部分所贡献的，通过算例分析了不同条间力假设模式下的滑面正应力及其两个贡献分量的分布。研究表明：滑体体积力（含坡面外力）贡献分量占主导地位，而土条间作用力的贡献分量较小。安全系数对滑面正应力分布不敏感。因此，在滑面正应力分布函数的构造上无需过分追求与真实分布之间的吻合度，可采用以占主导贡献地位的滑体体积力（含坡面外力）贡献分量为核心函数，选用含两个待定参数的修正函数来逼近土条间作用力贡献分量的分布。研究成果规范了滑面正应力的假设模式，具有一定的理论和应用价值。

Selection of constitution and distribution model of normal stresses over slip surface of slope

The method of slope stability analysis based on the assumption distribution of normal stresses over the slip surface is a progress of limit equilibrium theory. To obtain a reliable safety factor, it is essential to analyze the composition and assumption pattern of normal stresses over slip surface of slope which are dependent upon the body and inter-slice forces. Examples are given to analyze the distribution and contribution components of normal stresses over the slip surface under different assumptions of inter-slice forces. The results show that: Contribution component of slide body forces (including slope external forces) is dominant; and inter-slice forces are smaller contribution component. The safety factor is insensitive to the distribution of normal stresses over the slip surface. So, it is not necessary to demand for the accordance between assumption normal stresses distribution and real normal stresses distribution over the slip surface. Then, the assumption distribution of normal stresses over the slip surface could constitute by the contribution component of body forces, chosen as the kernel function, and the contribution component of inter-slice forces which could be approximated by a modifying function with two undetermined parameters. The research results have disciplined the assumption patterns of normal stresses, and have practical and theoretical value.