沉井法是通过松散不稳定含水层的一种简易价廉的建井方法。目前由于受下沉深度的限制,通过较厚的表土层(150米以上)还有困难。沉井主要由刃脚和井壁组成。其原理是靠沉井的自重克服土层对刃脚下部的正面阻力和土层对沉井的侧面阻力而下沉的。因此,如何处理好下沉力与下沉阻力这对矛盾,将是沉井法能否达到预期效果和增加适应性的关键。一、沉井壁厚的设计下沉深度确定后,井壁的自重主要取决于井壁的厚度。对于沉井法来说,井壁厚度一般先按强度和下沉重率要求分别进行壁厚预算,再将两者中的大值代入下沉条件式,进行壁厚的验算。1.按强度计算井壁厚度目前,我国沉井一般多为混凝土或钢筋 The open caisson method is a simple and inexpensive well-building method through loose unstable aquifers. At present, due to the depth of subsidence, it is still difficult to pass through thicker topsoil (above 150 meters). The caisson is mainly composed of cutting edge and well wall. The principle is to rely on the self-weight of the caisson to overcome the frontal resistance of the soil to the lower edge of the blade and the sinking of the soil to the lateral resistance of the caisson. Therefore, how to handle the contradiction between sinking force and sinking resistance will be the key to whether the open-pit method can achieve the desired effect and increase adaptability. First, the thickness of the design of the sinking wall After the sinking depth is determined, the self-weight of the well wall mainly depends on the thickness of the well wall. For the open caisson method, the thickness of the wellbore wall is generally firstly calculated according to the strength and lowering rate requirements, and then the large value of the two is substituted into the sinking condition type for checking the wall thickness. 1. Calculation of wall thickness by strength Currently, open caisson in China is generally mostly concrete or steel