给排水管底土层的承载力分析

Analysis of Bearing Capacity of Soil at the Bottom of Water Supply and Drainage Pipeline

管道是公路工程和城市建设的重要组成部分,合理的管底土层承载力是避免管道破坏的重要保障之一。为研究管底土层承载力,对管道等效成条形基础、检查井等效成矩形或圆形基础,对管道设计通用图纸有关承载力规定的合理性进行详细讨论,结果表明:当深度大于1 m时,满足要求时的土层承载力特征值很小;对于检查井等结构物,随外径和地表单侧轮重的不同,对检查井底部土层承载力特征值的要求也是不同的,甚至会出现承载力特征值非常大的情况,说明通用图纸规定的要求不再适用。当土层承载力不足时,应采用换填垫层的进行处理,同时应满足软弱下卧层的承载力要求。垫层会增加沉降差,且管底土层越好,垫层的增加作用越不明显。然而总得来说,管道的沉降差是非常小的,不足以造成管道损坏。根据实际情况,为最大限度避免管道破坏,同时使管道沉降、管底承载力均满足要求,提出了一个简单的管底土层处理原则。

Pipeline is an important part of highway engineering and urban construction.Reasonable bearing capacity of soil at the bottom of pipe is one of the important guarantees to avoid pipeline damage.To study the bearing capacity of the soil under the pipe,the pipeline was equivalent to a strip foundation,and the inspection well was equivalent to a rectangular or circular foundation.The rationality of the general requirements for the bearing capacity of the general drawings of the pipeline was discussed in details.The results show that when the depth is longer than 1 m,the bearing capacity meets the requirements.For structures such as inspection wells,the requirements for the bearing capacity are different depending on the outer diameter and the side wheel weight of the ground form,and even the case where the bearing capacity characteristic value is very large may occur.This means that the requirements specified in the general drawings are no longer applicable.When the bearing capacity of the soil layer is insufficient,the replacement of the cushion should be used,and the bearing capacity of the weak underlying layer should also be met.The cushion layer is to increase the settlement difference,and the better the soil layer under the pipe,the less obvious the increase effect of the cushion.In general,however,the difference in settlement of the pipeline is very small and is not sufficient to cause damage to the pipeline.According to the actual situation,in order to avoid the pipeline damage to the greatest extent,and at the same time make the pipeline settlement and the bearing capacity of the pipe bottom meet the requirements,a simple principle of soil treatment was proposed.