长沙地铁砂卵石地层盾构紧邻桥桩施工隔断保护研究

发布时间：2018-05-06 19:42

本文选题：砂卵石地层 + 邻近结构物　；参考：《中南大学》2014年硕士论文

【摘要】：结构物隔断保护作为一种临时的施工保护措施,其设计带有很大的经验性,在施工前对其保护效果也存在着较大的不确定性。因此,对盾构邻近结构物施工隔断保护研究将具有重要的现实意义。本论文依托长沙地铁砂卵石地层盾构穿越新中路立交桥L匝道工程,采用现场监测及数值分析手段,研究了长沙地铁砂卵石地层盾构施工地表沉降特征,针对所穿越既有构筑物特点进行盾构紧邻桥桩施工隔断保护研究。本文主要研究内容和成果如下： (1)结合盾构侧穿新中路立交桥L匝道工程地质条件和环境条件,对其施工风险进行了系统的分析。由于本工程不确定风险因素较多,施工风险高,为保证上部结构安全,提出了旋喷桩加固隔断保护的风险控制措施； (2)分析了长沙地铁砂卵石地层地质条件,归纳总结了砂卵石地层盾构施工地表沉降特征及优化掘进参数,为今后类似盾构施工提供参考；采用位移控制有限元法(DCM法),研究了砂卵石地层盾构施工地层变形特性,并将计算结果与现场实测数据进行对比,验证了DCM法的合理性和准确性； (3)通过对隔断结构的作用机理和对隧道开挖地层变形影响规律进行研究,得到了隔断结构的主要设计参数(刚度EI、隔断范围tanφ、嵌入深度h1)对隔离效果的影响规律,为隔断结构的优化设计提供依据；对长沙常见上软下硬地层与均匀地层进行了隔断效果对比,分析了隔断结构的地层适用性； (4)选取侧穿新中路桥桩中风险较高断面,采用Ansys三维数值模型,研究了有无旋喷桩隔断时盾构隧道开挖对邻近桩基变形和内力的影响,分析旋喷桩加固隔断保护效果。同时,结合地中水平位移、地表沉降和地下水位监测,验证了旋喷桩加固隔断保护的有效性。图99幅,表29个,参考文献90篇。
[Abstract]:The structure partition protection is a temporary construction protection measure, its design has a great empiricism, and there is a great uncertainty in the protection effect before construction. Therefore, it is of great practical significance to study the protection of the construction partition of the adjacent structure of the shield. This paper relies on the shield crossing of the sand gravel stratum in Changsha Metro. In the L ramp project of Xinzhong Road overpass, the ground subsidence characteristics of the shield construction in Changsha subway sand gravel stratum are studied by means of field monitoring and numerical analysis. The main research contents and results are as follows:
(1) combined with the engineering geological conditions and environmental conditions of the L ramp of the new Middle Road overpass on the side of the shield, the construction risk was systematically analyzed. The risk control measures were put forward because the project was uncertain and the risk factors were more, the construction risk was high, and the safety of the superstructure was ensured.
(2) the geological conditions of sand pebble formation in Changsha subway are analyzed, the characteristics of ground settlement and optimization of tunneling parameters are summarized, which provide reference for the similar shield construction in the future. The displacement control finite element method (DCM method) is used to study the deformation characteristics of the shield construction in sand gravel stratum, and the calculation results are compared with the site. Comparing the measured data, the rationality and accuracy of the DCM method are verified.
(3) through the study of the action mechanism of the partition structure and the law of the influence of the tunnel excavation on the formation deformation, the influence rules of the main design parameters (stiffness EI, partition Tan phi, embedded depth H1) on the isolation effect are obtained, which provide the basis for the optimization of the partition structure, and the common upper soft under the hard strata and the uniformity in Changsha. The effect of the partition is compared, and the applicability of the partition structure is analyzed.
(4) select the high risk section in the side of the new middle road bridge pile, and use the Ansys three-dimensional numerical model to study the influence of the shield tunnel excavation on the deformation and internal force of the adjacent pile foundation when the non rotating jet pile is separated, and analyze the protective effect of the rotary spraying pile to reinforce the partition. Meanwhile, the horizontal displacement in the ground, the surface settlement and the monitoring of the groundwater level are used to verify the jet grouting pile. The effectiveness of reinforced partition protection is shown in Figure 99, table 29, and 90 references.

【学位授予单位】：中南大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U231.3;U455.43

【参考文献】