基于模糊理论的盾构掘进参数对周围土体变形影响的研究

发布时间：2018-12-20 18:49

【摘要】：近年来,土压平衡盾构法隧道施工技术越来越广泛地在全国软土地区应用。然而软土中盾构隧道施工会不同程度地扰动周围地层,进而引起地表沉降,沉降过大将危及邻近建筑物、地下管线等的安全。软土地区土压平衡盾构机在穿越重要区域过程中,优化不同掘进参数以降低对地表沉降的影响是十分必要的。针对天津地铁二号线建国道站至天津站盾构掘进工程,基于盾构机参数实测结果分析了盾构力学掘进参数中盾壳摩擦力、掌子面压力和刀盘扭矩与掘进速度的关系,运用模糊统计试验定义了盾构正常掘进状态及该状态下力学掘进参数的标准值和偏差取值范围,建立了可考虑盾壳摩擦力、掌子面压力和刀盘扭矩影响的三维有限元模型,分析了上述因素对周围地层沉降、应力历史影响的规律,并通过空旷场地下的实测数据对计算结果进行验证。在盾构机正常掘进状态下,将盾壳摩擦力、掌子面压力和刀盘扭矩在各自取值范围内出现偏差对土体变形的影响进行分析。盾构掘进速度不同时,各力学掘进参数的取值范围不同;盾构正常掘进状态时对地表附近土体沉降影响最敏感的掘进参数是盾壳摩擦力,组合参数偏差对地表沉降的影响也是由盾壳摩擦力主导;对隧道周围土体沉降的影响,根据盾构掘进阶段的不同存在抵消和叠加效应;掘进速度较高时的力学掘进参数对地层变形的影响有抑制的作用;一定环数内出现掘进参数偏差对地表变形的影响是随偏差环数而线性增长的,超出一定环数后参数偏差对变形的影响趋于稳定。以该区间盾构掘进中的力学掘进参数出现偏差为底事件、以地表沉降控制为目标建立了风险事故树,并将以上参数化分析的沉降计算结果和盾构机掘进参数的实测数据作为待评价指标,引入工程风险分析方法中。针对盾构正常掘进过程中盾壳摩擦力、刀盘扭矩、掌子面压力和注浆压力对周围地表沉降影响,进行了风险损失、风险失效概率的定量风险分析,最后得出了天津软土地区的深埋盾构在正常掘进状态时以力学掘进参数为致险因子的风险值分级与排序,从而对盾构掘进引起变形的精细化控制提供参考。
[Abstract]:In recent years, soil pressure balance shield tunneling technology is more and more widely used in soft soil areas of China. However, the construction of shield tunnel in soft soil will disturb the surrounding strata to varying degrees, and then cause ground subsidence, which will endanger the safety of adjacent buildings, underground pipelines and so on. It is necessary to optimize different tunneling parameters in order to reduce the influence on surface subsidence during the process of soil pressure balance shield machine passing through important areas in soft soil area. In view of shield tunneling engineering from Jianguo Road Station to Tianjin Station of Tianjin Metro Line 2, the relationship between shield shell friction, face pressure, cutter torque and tunneling speed is analyzed based on the measured results of shield machine parameters. The standard value and deviation range of mechanical tunneling parameters in shield tunneling are defined by fuzzy statistical test, and a three-dimensional finite element model considering the influence of shield shell friction, face pressure and cutter head torque is established. The law of the influence of the above factors on the settlement and stress history of the surrounding strata is analyzed, and the calculated results are verified by the measured data of the open field underground. Under the normal tunneling condition of shield machine, the influence of shield shell friction, face pressure and cutter torque on soil deformation is analyzed. When the speed of shield tunneling is different, the range of mechanical tunneling parameters is different. The most sensitive tunneling parameter to the settlement of soil near the ground is the shield friction, and the influence of the combined parameter deviation on the surface settlement is dominated by the shield friction. According to the different stages of shield tunneling, the effect of offset and superposition exists on the settlement of soil around the tunnel, and the influence of mechanical tunneling parameters on the formation deformation is restrained when the tunneling speed is high. The effect of drift parameter deviation on surface deformation increases linearly with the number of ring deviations within a certain number of rings, and the effect of parameter deviation on surface deformation tends to be stable after the number of rings exceeds a certain number of rings. Taking the deviation of mechanical tunneling parameters in shield tunneling in this section as the base event, the risk accident tree is established with the control of surface subsidence as the target. The calculated results of the above parameterized analysis and the measured data of the tunneling parameters of shield machine are taken as the indexes to be evaluated, and the method of engineering risk analysis is introduced. In view of the influence of shield shell friction, cutter head torque, face pressure and grouting pressure on the surface settlement during the normal tunneling of shield, the risk loss and risk failure probability are analyzed quantitatively. Finally, the classification and ranking of the risk value of the deep buried shield in Tianjin soft soil area with mechanical tunneling parameters as the risk factors are obtained, which provides a reference for the fine control of the deformation caused by shield tunneling.
【学位授予单位】：天津大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：U455.43

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