摘要
基于长沙地铁4号线全方位高压喷射(MJS)桩试验,采用流固耦合数值模拟方法研究富水砂土地层中水平MJS桩的施工扰动影响。对各施工阶段引起的地层超静孔隙水压力和地层变形进行分析,揭示水平MJS桩施工对地层环境的影响规律。数值模拟结果与现场实测孔压回归分析获得的趋势线基本一致,验证了数值模型的合理性。通过数值分析表明:在喷浆施工阶段,MJS桩孔扩张引起上覆土层隆起;在喷浆结束成桩阶段,MJS桩体受到地层压力产生压缩引起上覆土层沉降。施工诱发超静孔隙水压力幅值约为50 kPa,影响范围为桩体10 m附近,富水砂土地层中孔压增量消散迅速,能够在桩体施工时间段内基本消散完毕。通过MJS法的主动排泥装置将地内压力限制在可控范围内,能够使其诱发的环境影响较小。
Based on the MJS(metro jet system)pile test of Changsha Metro Line 4 as the background,the fluid-mechanical coupling numerical simulation method is adopted to study the environmental disturbance from the horizontal MJS pile construction in water-rich sandy stratum.Excess pore pressure and deformation in stratum induced at each construction stage are analyzed.The pattern of how horizontal MJS pile construction influences stratum environment is revealed.The numerical simulation results and the trend line obtained by pore pressure regression analysis of the field test data are generally consistent,verifying the rationality of the numerical model.The numerical analysis shows that in the shotcrete construction stage,the expansion of the MJS pile hole causes the overlying soil layer to bulge;at the end of the shotcrete stage,the MJS pile is compressed because of stratum pressure and causes the overlaying soil layer settlement.The increase of pore pressure induced by construction is about 50 kPa,and the range is within 10 m from the pile.The increment of pore pressure can be dissipated rapidly within the construction period of the MJS pile.The MJS method of active sludge drainage system limits the stratum excess pressure within controllable range,which can make the induced environmental impact smaller.
作者
赵宝华
谭鑫
王光辉
黄明华
黎腾龙
ZHAO Baohua;TAN Xin;WANG Guanghui;HUANG Minghua;LI Tenglong(China Railway Tunnel Consultants Co.,Ltd.,511458,Guangzhou,China;不详)
出处
《城市轨道交通研究》
北大核心
2022年第4期65-69,74,共6页
Urban Mass Transit
基金
湖南创新型省份建设专项经费项目(2019GK1010)
国家重点研发计划项目(2019YFC1511101)。
关键词
全方位高压喷射桩
环境影响
富水砂土地层
MJS(metro jet system)pile
environmental impact
water-rich sandy stratum
