天然软土地基路堤临界高度一种计算方法研究

考虑地表硬壳层应力扩散作用、硬壳层的抗剪强度、中间主应力 对地基承载力的影响，从实际情况下土的静止侧压力系数出发，依据极坐标表示的弗拉曼公式和统一强度理论，推导出天然软土地基临塑与临界荷载公式，提出天然软土地基上路堤临界高度的一种计算方法。结合算例，探讨了软土层和硬壳层静止侧压力系数 、中间主剪应力系数 取不同值对路堤临界高度 的影响。结果表明： 与 的改变对路堤临界高度 影响很大，新的理论公式更能反应软土地基承载力的实质，对覆有硬壳层的软土地基上路堤的修筑具有一定的指导意义。

Study of a calculation method of critical height of embankment on natural soft soil foundation

The effect of stress dispersion and shear strength of dry crust has been considered, the effect of intermediate principal stress is studied; and the realistic coefficient of lateral earth pressure has been undertaken. Reference has been made to the Flamant formula of polar coordinate system and unified strength theory. Therefore, new formulas of the critical edge pressure and critical loading of natural soft soil foundation are deduced. A calculation method of the critical height of embankment on natural soft soil foundation is also proposed. In accordance to a practical example, this paper also expounds a comparative analysis which has been made on calculation results of the critical height of embankment, different values of coefficients of lateral earth pressure of soft soil layer and dry crust and intermediate principal stress b are taken into consideration. This paper also studies the effect of these factors on the critical height of embankment . It is shown that the changes of and b have significant influences on the critical height of embankment . New formulas can more accurately reflect the essentials of soft soil foundation bearing capacity. It is of great significant to the construction of embankment in the natural soft soil foundation covered with dry crust.