This paper is aimed at identifying the degree to which projects disturb strata.The research involves establishing the new route of the Muxiyuanqiao South Station and Daxingmen Station using the mine method;based on the measured data, developing the three-dimensional numerical model using the FLAC3D software;and thereby investigating the influence of the pipe construction on the perturbation deformation in the sand and gravel stratum.The results show that the disturbances of the upper strata by the curtain construction are dominated by sediment;the pre-support system in the sand and gravel strata could reduce the disturbance of the upper soil layer by the tunnel construction;and the construction of the new tunnel under the action of the pipe pre-support system allows the existing structure of the settlement deformation to be controlled within the allowable range.The study could provide references for the design and construction of the pre-support system for the underground engineering.%为判断工程施工对地层的扰动程度,依托矿山法新建北京地铁8号线木樨园桥南站-大红门站区间正线下穿既有10号线盾构区间工程,提出以土层沉降作为施工扰动微变形判断依据,进行钢管顶进施工现场实验,并在实测数据基础上采用FLAC3D软件建立三维数值模型,研究砂卵石地层中管幕施工对地层扰动变形的影响.结果表明,管幕施工对上部地层的扰动以沉降为主;砂卵石地层中管幕预支护体系能够减小隧道施工对上部土层的扰动;在管幕预支护体系作用下进行新建隧道的施工,能够将既有结构的沉降变形控制在允许范围内.研究结果可为相关地下工程管幕预支护体系设计、施工提供参考.
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