【摘要】 古运河暗渠下穿石太高速公路,是南水北调中线工程总干渠上的一座大型河渠交叉建筑物。该暗渠为三孔联拱涵结构,其施工条件极其复杂,暗渠段土质多为细砂和中细砂,开挖分部多,且高速公路上通行车辆荷载较大,是全国此类施工难度最大和开挖宽度(25.6 m)最大的项目。为配合施工,采用FLAC3D三维快速拉格朗日差分方法分析软件,按实际的开挖顺序和施工工艺,对下穿高速公路段开挖过程进行了数值模拟。由此得出下穿段暗渠施工引起的地层变形、应力和塑性区分布,数值计算结果表明,下穿段暗渠施工方案是合理可行的,计算结果为地层加固范围提供了依据,对下穿段暗渠施工有指导作用。施工实践也证明了依据数值计算结果所采取的施工辅助措施对确保地表线路安全和隧道施工安全效果明显。更多还原

【Abstract】 The underdrain of ancient canal beneath Shi-Tai Expressway is a large-scale graff cross structure of main channel in middle route project of South-to-North water diversion.This underdrain is three-arch culvert structure,where construction condition is very complex.The soil of underdrain constructed using partial excavation method are fine sand and medium-fine sand mostly,and passing vehicle load on expressway is heavy;so the construction is the most difficult one and the excavation width(25.6 m) is the widest for similar domestic engineering.The construction process according to actual construction sequence and craft is simulated by using FLAC3D software.The stratum deformation,the stress and the distribution of plastic region are discussed in detail.The calculation result indicates that the underdrain construction scheme of underpass is reasonable;and it has guidance function on the underdrain construction scheme of underpass;and it also provides basis for the range of stratum reinforcement.The practice of construction process verifies that the assistant reinforcement measures are effective for the safety of railway lines and tunnels based on the results of numerical simulation.更多还原