摘要:
针对盾构隧道施工过程中常出现的管片上浮问题，通过自主研发的同步注浆浮力测试装置，揭示了典型单、双液浆内净浮力随时间的变化规律，并采用ExpDec2 模型建立净浮力-时间的通用数学表达式。随后综合考虑浆液浮力消散特性、管片自重、盾构推力、地层荷载以及盾尾约束，通过有限元软件ABAQUS建立盾构隧道管片上浮计算模型，探明了典型单、双液同步注浆作用下管片衬砌结构的上浮变形规律，并结合工程实测数据验证了数值计算的合理性。研究结果表明：1）同步注浆浆液净浮力随时间的变化可分为直线段Ⅰ和曲线段Ⅱ两个阶段，且净浮力降至零时浆液仍处于流塑状态，远未达终凝时间；2）建立的管片-注浆层计算模型能够揭示被逐渐胶凝浆液所包裹的管片上浮特性，与实测数据基本一致，可为类似工程管片上浮设计提供依据；3）与单液浆相比，双液浆浮力消散时间和物理终凝时间均非常短，从而能够快速腔固管片而大大抑制管片上浮，由此若实际工程管片上浮严重，建议选取胶凝时间快、早期强度高的同步注浆浆液。
Abstract:
In view of the problem of segment floating that often occurs during shield tunnel construction, the variation rule of net buoyancy with time in typical single-component grout and two-component grout has been revealed through the self-developed test device, and the ExpDec2 model has been used to establish the general mathematical expression for the change of net buoyancy with time. Subsequently, considering the net buoyancy dissipation characteristics of the grout, the self-weight of the segment, the shield thrust, the ground load and the shield tail constraints, the ABAQUS is used to establish the computational model of the segment floating. The floating pattern of segment lining structure under the action of typical single-component grout and two-component grout is proved, and the reasonableness of numerical calculation is verified by the measured data of the actual project. The results show that: 1) The process of grout net buoyancy dissipation with time can be divided into two stages, which is the linear section and curve section. And when the net buoyancy falls to zero, the grout is still in the state of flow plasticity, far from reaching the final setting time; 2) The established calculation model of segment-grouting can reveal the floating characteristics of the segment wrapped by the gradual cementing grout, which is basically consistent with the measured data and can provide a basis for the design of segment floating; 3) Compared with single-component grout, the buoyancy dissipation time and physical final setting time of two-component grout are very short, which can quickly restrict segment and greatly reduce the amount of segment floating. Therefore, if the floating of the segment is serious in the actual project, a grout with fast setting time and high early strength is recommended.
百度学术
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