矩形SMW工法工作井土体反力计算方法的研究

Study on calculating methods of earth counterforce in rectangular working shaft by SMW methods

对采用型钢水泥土复合挡土墙(Soil Mixing Wall,SMW)建造的矩形工作井在顶力反力作用下的受力机理进行分析,假定承载后背竖向土体反力呈拟正态分布、水平向土体反力呈均匀分布,求得后背土体所能承受的最大土体反力计算公式。考虑前壁土体达到主动状态,得到工作井最大土体反力和允许顶力的计算公式。算例分析表明:采用梯形分布计算得到的后背最大土体反力值要略大于文中方法计算结果;在黏性土中,文中方法采用水土合算计算得到的允许顶力值与实测值较吻合。

The loading mechanism under the action of jacking counterforce of rectangular working shaft by soil mixing wall （SMW） methods is investigated. Assuming the horizontal earth counterforce distributed equably, vertical earth counterforce at the back of loaded wall is considered as quasi-normal distribution, a formula for calculating maximal earth counterforce at the back of loaded wall is obtained. Assuming the soil at the front of loaded wall is at active state, formulas for the maximal earth counterforce and permitted jacking force of working shaft are obtained. The analytical calculation results of an example show that the maximal earth counterforce at the back of loaded wall by trapezoidal distributing method is some greater than one with the method presented in text. The permitted jacking force calculated by estimating water and earth pressure together in cohesive soil is highly close to the maximal jacking force measured in field.