一、概况今年一月份在掘进浅井时,为了上下井方便我們在井壁的泥土中釘了三个作梯子使用的木桩,几天后表土的风化岩石塌落,一旁井壁的泥土也随之塌落,但是釘有木桩的壁沒有塌落。于是我們就把实践中的现象提高到理性方面來認識,根据土壤力学的原理又进一步观察和分析了土壤的性質及其他地方的塌落现象,发现土的滑动面往往不是斜面而是曲面,有些地方塌落不是瞬时的,而是有一段时間(有的經过几天,有的經过数月),尤其經过暴雨,塌落现象到处可见。根据上述现象的观察与分析,只要打入土中的拉杆与土分子間所产生的摩擦力大于塌落所产生的压力 I. Overview When we drilled a shallow well in January this year, in order to facilitate the use of the upper and lower wells, we nailed three wooden stakes used as ladders in the mud of the wellbore. After a few days, the weathered rock on the topsoil collapsed and the clay on the side of the well borehole followed. It fell, but the wall with the stakes did not collapse. So we improved the phenomenon in practice to a rational aspect. According to the principle of soil mechanics, we further observed and analyzed the nature of the soil and the collapse phenomenon in other places. We found that the sliding surface of soil is often not a slope but a curved surface. The collapse of places is not instantaneous, but there is a period of time (some days after a few days, and some after a few months). Especially after heavy rain, the phenomenon of collapse can be seen everywhere. According to the observation and analysis of the above phenomena, as long as the friction between the tie rod and the soil molecule that is driven into the soil is greater than the pressure produced by the collapse