富水砂层盾构始发MJS工法桩的应用及分析  

Application and Analysis of MJS Pile in Shield Starting of Water-rich Sandy Stratum

作　　者：熊仲明[1] 覃泽宏 蔡虹 汪肆卜 XIONG Zhongming;QIN Zehong;CAI Hong;WANG Sibo(Xi′an University of Architecture and Technology,Xi’an,Shaanxi 710000,China;China Tiesiju Civil Engineering Group,Hefei,Anhui 230041,China)

机构地区：[1]西安建筑科技大学,西安710000 [2]中铁四局集团有限公司,合肥230041

出　　处：《铁道工程学报》2021年第3期8-12,64,共6页Journal of Railway Engineering Society

基　　金：国家自然科学基金项目(51278395);住建部科学技术基金项目(2016-k5-044);陕西省自然科学基础研究计划重点项目(2018JZ5008)。

摘　　要：研究目的:富水砂层地区某地铁区间盾构始发时破洞门遭遇困难。为解决该部位的盾构井加固难题,通过有限元数值模拟研究后采用MJS工法桩加固,使盾构得以安全进行,且数值模拟的计算结果与现场实测数据对比相一致。研究结论:(1)采用适用的地内应力系数与水泥掺量比例,在深富水、厚砂砾层情况下,MJS工法桩成桩质量好、压力可稳定控制、对土体扰动小;(2)MJS工法桩扩孔造成的土体侧向位移与地表沉降随着侧压力增大而增大,随着水泥掺量的加大而减小;(3)对于苏北黄泛区富水砂层地区,在1.6倍地应力的压力控制下,水泥掺量为40%时,扩孔成桩对周围土体的扰动最小,成桩效果最好;(4)MJS桩在淮安地区运用效果很好,可为其他富水砂层地区的盾构施工提供参考。Research purposes: It is difficult to break a tunnel door when shield tunneling starts at a subway section in water-rich sandy stratum. In order to solve the problem of shield shaft reinforcement in this area, MJS pile reinforcement method is adopted after finite element numerical simulation research, which makes shield tunnel work safely, and the calculation results of numerical simulation are consistent with the field measured data. Research conclusions:(1) MJS piles are of good quality, stable pressure control and little disturbance to soil mass under the condition of deep water-rich and thick gravel layer by adopting the appropriate ratio of in-situ stress coefficient and cement content.(2) The lateral displacement of soil mass and ground settlement caused by MJS pile enlargement increase with the increase of side pressure and decrease with the increase of cement content.(3) For the water-rich sandy stratum in the Yellow River flooding area of North Jiangsu, under the control of 1.6 times stress and 40% cement content, the disturbance of expanded hole pile to surrounding soil body is the smallest and the effect of pile formation is the best.(4) MJS piles are very effective in Huai’an area and can provide reference for shield construction in other water-rich sand layer areas.

关 键 词：盾构井 MJS工法桩 始发端 加固 

分 类 号：TU441.4[建筑科学—岩土工程]