环锚预应力混凝土衬砌结构锚具槽区域的应力状态分析

发布时间：2018-03-25 03:29

本文选题：锚具槽　切入点：预应力混凝土衬砌　出处：《天津大学》2014年硕士论文

【摘要】：无粘结环锚预应力衬砌结构是应用在水工隧洞中的一种新型结构形式，该结构主要适用于衬砌围岩地质条件较差、衬砌中的水压力较大以及衬砌开裂水渗入围岩后能够导致周围建筑物失稳的水工隧洞结构中。无粘结预应力衬砌结构作为一种新型的衬砌结构形式具有其特殊的优点：无粘结衬砌中钢绞线采用双圈环绕形式，能够使衬砌中的压应力分布更均匀，锚索的沿程预应力损失更小，，与有粘结衬砌相比有效预压应力大，衬砌的厚度可以适当减小，这样就能够节省材料减小开挖量，大大降低了施工的难度和工程造价，有效的加快施工的进度。鉴于无粘结环锚预应力混凝土衬砌的优势，可以看出这种结构在我国水工隧洞中有着广阔的应用前景。目前，这种衬砌形式只在小浪底工程的三条排沙洞和大伙房水库输水隧洞中得到应用，从这两个工程的运行情况来看，该结构也暴露出一些问题，尤其是锚具槽部位，通过对小浪底工程试验段进行观测发现，小浪底锚具槽存在漏油现象，锚具槽部位是整个结构的薄弱环节。本文主要应用ANSYS有限元分析软件对小浪底2号排沙洞建模分析，分别对锚索张拉阶段的施工期和加水压后的运行期的锚具槽区域的应力状态进行分析，并将施工期的结果与2号排沙洞试验段的监测数据进行对比，看出两者具有很好的一致性。计算结果表明，锚具槽部位的受力状态是整个结构最复杂的，最大最小环向应力均出现在锚具槽附近，轴向和径向还出现了较小的拉应力。为了解决这个问题，本文在最后一章对锚具槽位置做了优化，并对其进行施工期和运行期的有限元分析，从结果可以看出，优化后的结构薄弱区范围明显减小，锚具槽附近的应力分布更均匀，对于今后的工程具有一定的参考价值。
[Abstract]:Unbonded ring anchor prestressed lining structure is a new type of structure used in hydraulic tunnel. The structure is mainly suitable for the poor geological conditions of surrounding rock of lining. As a new type of lining structure, unbonded prestressed lining structure has its own special characteristics, such as high water pressure in lining and cracking water infiltration into surrounding rock, which can lead to instability of surrounding buildings. Advantages: the steel strands in the unbonded lining are in the form of double rings. It can make the distribution of compressive stress in lining more uniform, and the loss of prestress along the Anchorage cable is smaller. Compared with the bonded lining, the effective preloading stress is larger, and the thickness of the lining can be reduced appropriately, which can save the material and reduce the excavation amount. It greatly reduces the construction difficulty and construction cost, effectively speeds up the construction progress. In view of the advantages of unbonded ring anchor prestressed concrete lining, it can be seen that this kind of structure has a broad application prospect in hydraulic tunnels in China. This type of lining is only used in the three sand discharge tunnels of Xiaolangdi Project and the water conveyance tunnel of Dahuofang Reservoir. Judging from the operation of these two projects, the structure also exposes some problems, especially the part of the Anchorage slot. By observing the test section of Xiaolangdi project, it is found that the leakage of oil exists in the Anchorage trough of Xiaolangdi, and the position of the Anchorage slot is the weak link of the whole structure. In this paper, the ANSYS finite element analysis software is mainly used to model and analyze the sand discharge tunnel No. 2 in Xiaolangdi. The stress state of the anchoring slot area during the construction period of the cable tension stage and the running period after adding water pressure is analyzed respectively. By comparing the results of the construction period with the monitoring data of the test section of No. 2 sand discharge tunnel, it is found that there is a good agreement between the two. The calculation results show that the stress state of the Anchorage slot is the most complex of the whole structure. In order to solve this problem, the maximum and minimum circumferential stresses appear near the Anchorage slot, and the axial and radial tensile stresses are smaller. In order to solve this problem, the position of the Anchorage slot is optimized in the last chapter. The finite element analysis of the structure during the construction period and the running period shows that the scope of the weak area of the structure after optimization is obviously reduced and the stress distribution near the Anchorage slot is more uniform, which has certain reference value for the future engineering.
【学位授予单位】：天津大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TV554

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