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锚具槽区域是预应力衬砌中应力状态最复杂的薄弱环节,运行期锚具槽区域的应力状态是判定预应力衬砌能否实现不裂不渗,或局部虽开裂但不产生渗漏的重要依据。结合小浪底排沙洞工程实例,采用ANSYS有限元计算方法,分别对锚具槽回填混凝土与衬砌黏结良好以及锚具槽端部出现不同开裂后衬砌结构的应力状态进行了分析,在设计水位下,回填混凝土均处于全面受拉状态,要避免开裂几乎是不可能的。在分析锚具槽区域出现不同开裂后应力状态的基础上,提出了一种“强调回填混凝土密实性,弱化与衬砌黏结作用”的设计思路,并进行了相应的计算分析,在此种设计思路下回填混凝土内部及新老混凝土结合面受拉状态得到很大改善,从而降低了锚具槽局部开裂的可能性,为类似工程的设计和施工提供了新思路。
The anchor groove area is the most complicated weak link of the stress state in the prestressed lining. The stress state of the anchor groove area in the operation period is important for judging whether the prestressed lining can realize the non-seepage or non-seepage, or the local crack but no leakage in accordance with. Combined with the example of Xiaolangdi sediment discharge tunnel project, the finite element method of ANSYS was used to analyze the stress state of the lining structure after different cracking at the end of anchor groove with good bonding between anchorage groove backfill concrete and lining, respectively. Under the designed water level, Backfill concrete are in full tension state, to avoid cracking is almost impossible. Based on the analysis of different post-cracking stress states in the groove region of anchorage, a design concept of “emphasizing the densification and weakening of lining concrete and the effect of lining adhesion” was put forward and the corresponding calculation and analysis were made. Under the design concept, the tension state of the internal surface of the backfilled concrete and the interface between the old and new concrete are greatly improved, which reduces the possibility of local cracking of the anchorage groove and provides a new idea for the design and construction of similar projects.