黄土高填方场地孔隙水压力的变化规律

于永堂 郑建国 张继文 梁小龙

摘 要：孔隙水压力是评价黄土高填方场地变形与稳定的重要参数。为探讨沟谷地形中黄土高填方场地孔隙水压力增长和消散规律，对陕北某黄土高填方工程进行了施工期和工后期的孔隙水压力监测和分析。结果表明：在分析超静孔隙水压力的增长和消散规律时，须扣除因土层压缩和地下水位变化而引起的静水压力变化值;孔隙水压力的增长和消散主要受地下水位和填土荷载的影响;土方填筑快，孔隙水压力增长快，反之，孔隙水压力增长慢，甚至消散;施工期的孔隙水压力增量与填土荷载增量呈近似线性关系，多级荷载的孔隙水压力系数小于0.2，土体始终处于稳定状态;工后期孔隙水压力消散缓慢，沉降达到完全稳定需要较长时间。

关键词：黄土;高填方场地;孔隙水壓力;监测

中图分类号：TU444 文献标志码：A 文章编号：2096-6717（2021）06-0010-07

Abstract： Pore water pressure is an important parameter to evaluate the deformation and stability of loess deep filled ground. In order to explore the law of pore water pressure increase and dissipation in the loess deep filled ground in the valley terrain， the pore water pressure monitoring and analysis were carried out during and after the construction period of a loess deep filled project in Northern Shaanxi. The results show that when analyzing the law of the increase and dissipation of the excess pore water pressure， the change of the hydrostatic pressure caused by compression of the soil layer and the change of the groundwater level must be deducted; the increase and dissipation of pore water pressure are mainly affected by groundwater level and filling load; when the filling speed of earthwork construction is fast， the pore water pressure increases fast. On the contrary， the pore water pressure increases slowly or even dissipates; The increase in pore water pressure during construction period has an approximately linear relationship with the increase in filling load. The pore water pressure coefficient of multistage load is less than 0.2， and the soil is always in a stable state; the dissipation of pore water pressure is slow in the following stage of construction， and it takes a long time for the settlement to reach complete stability.

Keywords： loess; deep filled ground; pore water pressure; monitoring

黄土丘陵沟壑区以“削峁填沟”方式开发建设用地，形成了一些厚度达几十米甚至上百米的黄土高填方工程。这些黄土高填方工程的原始沟谷中常分布有一定厚度的冲洪积土和淤积土层，这些土层具有结构松散、含水量高等特点，在上部大厚度填土荷载作用下，容易产生较大的变形和较高的孔隙水压力。高孔隙水压力的存在，会使土中有效应力降低，进而控制和影响高填方场地的变形与稳定，因此，有必要在黄土高填方工程中进行孔隙水压力监测和分析。

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