流砂地层大管径顶管施工技术

Construction Technology for Large-diameter Pipe Jacking in Quicksand Formations

东莞市小海河水体联通工程中跨越某供水渠采用顶管法,管径DN1500钢筋混凝土III级管,顶管穿越中粗砂层,中粗砂层透水系数(cm/s)1.113E-03,分析为中等透水,地下水位4.8 m,地下水位较高,某供水渠基础桩基间净距离为9.8 m,桩长13.6 m,且位于顶管段中部。由于中粗砂层透水性强,顶进过程中,容易出现流砂引起周围塌方,并且某供水渠桩基础净间距为9.8 m,该工程的主要施工难点就在于顶管段。

In Xiaohai River Water Connection Project in Dongguan City,the top pipe method is used to cross a certain water supply channel,with a diameter of DN1500 reinforced concrete Grade III pipe.The pipe jacking passes through a medium coarse sand layer with a permeability coefficient(cm/s)of 1.113E-03,which is analyzed to be moderately permeable.The groundwater level is 4.8 m and relatively high.The net distance between the foundation piles of a certain water supply channel is 9.8 m,the pile length is 13.6 m,and it is located in the middle of the top pipe section.Due to the strong permeability of the medium coarse sand layer,it is easy for sand to flow and cause surrounding collapse during the jacking process.And the net spacing between the pile foundations of a certain water supply channel is 9.8 m.The main construction difficulty of this project lies in the pipe jacking section.