The Environmental Rehabilitation Research for Manhole Covers on City Roads

Abstract

In order to facilitate inspection and maintenance for municipal public pipelines located below urban roads, more and more manholes were set up on the road surfaces. However, due to various inadequate design and construction etc., the manhole suffered most serious diseases such as collapse of wellhead, broken up of pavement around well, subsidence of manhole and damage of internal well structure. Which not only harms its life span, but also affects the driving safety and the city appearance. Firstly, this work investigated the manhole diseases of typical roads in cities of Changsha etc. and concluded that there are only two main types of road manhole diseases. The most prominent one is the pavement damages. The second one is the wellhead subsidence greater than 20mm. Secondly, the main causes of manhole disease was found out from the aspects of both design and construction. In design, the lack of details of wells and its surrounding backfill materials are main causes. In terms of construction, there are many problems such as insufficient attention to quality control, inadequate operation of key processes and lower level of construction refinement. Finally, systematic and comprehensive measures to deal with various kinds of diseases of manhole in not only design and construction but also prevention and restoration were presented.