大断面类矩形顶管壳体土压及顶进阻力分析--以上海淞沪路-三门路下立交工程为例

Analysis of Shell Earth Pressure and Jacking Force of Quasi-Rectangular Pipe Jacking with Large Cross-Section:a Case Study on Underpass Project at Songhu Road-Sanmen Road in Shanghai

为分析类矩形顶管机头的挤土效应,采用理论与数据分析相结合的方法,将上海淞沪路-三门路下立交大断面类矩形顶管工程中顶管机壳体土压力及顶进阻力监测结果与规范理论值进行对比,并引入经验计算系数。研究表明:1)按土柱理论和朗肯土压力理论计算的顶管机壳体土压力偏小;2)顶进阻力与推进里程呈线性关系,斜率为单位长度管道外壁摩擦阻力,截距为顶管机迎面阻力;3)《给水排水管道工程施工及验收规范》2008版和1997版中给出的顶管隧道单位长度管道外壁摩擦阻力计算方法均是以圆形截面为基准的,对于本工程的类矩形顶管隧道,2008版的计算结果较实际值小20%以上;4)对于上海砂质粉土地层,控制土压力侧向系数建议取0.8。

The monitoring results of shell earth pressure and jacking force of quasi-rectangular pipe jacking with a large cross-section in an underpass project at Songhu Road-Sanmen Road are compared with calculated results in codes using a quantitative method of theoretical and data analysis.The empirical coefficient is introduced to analyze the squeezing effect of quasi-rectangular pipe jacking head.The results show the following.(1)The calculated shell earth pressure using the soil column and Rankine earth pressure theories is relatively small.(2)The jacking force is linear with the mileage,where unit external friction is the slope,and frontal resistance is the intercept.(3)The circular section is the basis of the calculation methods of the unit external friction of quasi-rectangular pipe jacking tunnel given in the 2008 and 1997 editions of Code for Construction and Acceptance of Water and Sewerage Pipeline Works.For the quasi-rectangular pipe jacking tunnel in this project,the calculation result from the 2008 edition is 20%smaller than the actual value.(4)For the sandy silt ground in Shanghai,the lateral coefficient of control earth pressure is recommended to be 0.8.