【作者】 宋健；

【导师】 苏卫国； 李承海；

【作者基本信息】 华南理工大学 ， 建筑与土木工程（专业学位）， 2018， 硕士

【摘要】 通常地铁隧道结构稳定性与其附近的桩基础建设存在明显的关系,随着桩基础荷载的变大,使得其受力情况出现了明显的变化,受此影响其隧道结构也会出现一定的改变,例如容易造成隧道衬砌开裂渗水之类的问题,这使得整个地铁系统的运行受到了一定的威胁。所以需要对桩基础荷载进行研究和分析,探索其对于隧道造成的影响以及作用机制,并针对性的采取预防策略。在本文中主要对上述影响机制进行了研究与分析,并采用有限元法方法构建了三维模型,编制了相关的计算程序,对影响隧道形变的多个因素进行了模拟和分析,并提出了预防和治理的方式,为相关实际工程提供借鉴和指导。(1)对桩基荷载效应以及隧道变形理论进行了详细的介绍,探讨了单桩竖向荷载的具体过程,总结了隧道纵向变形的影响因素。研究发现:(1)沉桩效应主要受施工工艺的影响,要根据具体的施工情况进行设计计算;(2)端承型、摩擦型群桩,两者桩长、桩径以及桩顶荷载如果保持了稳定,隧道位移则主要受到桩隧间距的影响,可以选择使用增大桩隧间距的方法来降低隧道位移。(2)综合分析空港大道跨线桥的工程地质资料,依据所开展的系列三维数值模拟计算结果及其分析,认为空港大道跨线桥建设项目的设计方案基本可行,但应充分注意桩基础施工可能触发场地潜在岩溶土洞诱发的坍塌风险,从而避免影响地铁结构安全和地铁运营安全。根据监测结果,发现旋挖桩施工技术对隧道结构变形影响都在可控范围内。(3)结合空港大道跨线桥建设项目工程地质条件、承台基坑开挖方式、桩基布置情况、桥型结构特点,以及地铁盾构隧道、中间风井和联络通道的结构特点进行建模。同时认为跨线桥建设对地铁结构的不利影响主要体现在:(1)跨线桥承台基坑开挖对地铁结构造成的干扰;(2)跨线桥近距离桩基施工引起的负面影响;(3)跨线桥荷载及运营荷载对地铁结构的负面影响等三个方面,为确保地铁结构安全和地铁运营安全提出相应的整治措施。更多还原

【Abstract】 Usually,the stability of subway tunnel structure is obviously related to the pile foundation nearby.With the increase of pile foundation load,the stress situation of subway tunnel will be changed obviously,and the tunnel structure will be changed,for example,it is easy to cause the cracking and seepage of tunnel lining,which makes the whole tunnel become complete.The operation of a subway system has been threatened.Therefore,it is necessary to study and analyze the pile foundation load,explore its impact on the tunnel and the mechanism of action,and take preventive measures.In this paper,the above-mentioned influence mechanism is studied and analyzed,and a three-dimensional model is constructed by the finite element method,and the relevant calculation program is compiled.Several factors affecting tunnel deformation are simulated and analyzed,and the prevention and treatment methods are put forward,which can provide reference and guidance for relevant practical projects.The details are as follows:(1)The load effect of pile foundation and the theory of tunnel deformation are introduced in detail,the concrete process of single pile vertical load is discussed,and the influencing factors of tunnel longitudinal deformation are summarized.It is found that:(1)pile-sinking effect is mainly affected by construction technology,which should be designed and calculated according to specific construction conditions;(2)end-bearing and friction pile groups,whose pile length,pile diameter and pile top load are stable,tunnel displacement is mainly affected by pile-tunnel spacing,so it is possible to choose to increase the pile-tunnel spacing.Method to reduce tunnel displacement.(2)Based on the comprehensive analysis of the engineering geological data of the Airport Avenue Crossing Bridge,a series of three-dimensional numerical simulation results and their analysis are carried out.It is considered that the design scheme of the Airport Avenue Crossing Bridge construction project is basically feasible,but the risk of collapse induced by the potential karst soil cave in the site may be triggered by the pile foundation construction should be paid full attention to.And to avoid affecting the safety of subway structure and subway operation safety.According to the monitoring results,it is found that the influence of rotary excavation pile construction technology on tunnel structural deformation is within controllable range.(3)Combining with the engineering geological conditions,foundation pit excavation method,pile foundation arrangement,bridge structure characteristics of the construction project of Airport Avenue Overpass Bridge,and the structural characteristics of subway shield tunnels,intermediate air shaft and connecting passages,the model is established.It is found that the force of subway structure is at a lower level,which induces the variable of subway structure stress.Smaller.At the same time,it is considered that the unfavorable influence of the construction of the overpass bridge on the subway structure is mainly reflected in the following three aspects:(1)the disturbance caused by the excavation of the foundation pit of the overpass bridge cap to the subway structure;(2)the negative influence caused by the construction of the short-distance pile foundation of the overpass bridge;(3)the negative influence of the overpass bridge load and the operation load on the subway structure,so as to ensure the subway structure Safety and safety of subway operation are proposed.更多还原