会人溪砌石拱坝局部加固研究

Study on Local Reinforcement of Huirenxi Masonry Arch Dam

会人溪浆砌石拱坝坝底厚度远小于现行规范及同类工程要求,致使最大拉应力超标,结构安全评定不满足要求,需进行加固处理。为此,基于ANSYS有限元软件编制有限元等效应力计算程序,计算原坝体应力结果,提出了培厚加固、肋墩加固等4种局部加固方案。通过加固后坝体应力分布情况,找到了最优加固方案和加固实施条件。研究表明,在坝体下游侧采用培厚加固、肋墩加固等局部加固方案可显著降低加固区应力,但在初始加固条件下(加固前上游水位139 m),各方案均无法满足拉应力控制标准;坝体上游侧加固区顶部易出现拉应力集中,最大拉应力与加固体型及加固前上游水位相关;对加固前上游水位进行敏感性分析,发现低水位有利于降低坝踵处拉应力,但易导致加固区顶部附近拉应力偏大;在方案2条件下,控制加固前上游水位介于130~134 m时可满足拉应力控制标准,为推荐方案。

The bottom thickness of Huirenxi masonry arch dam is far less than the standard and similar engineering requirements, resulting in the maximum tensile stress exceeding the standard. The structural safety assessment does not meet the requirements, and it needs to be strengthened. Based on ANSYS, a finite element equivalent stress calculation program was compiled to calculate the stress of the dam body. The four local reinforcement schemes such as thickening reinforcement and rib pier reinforcement were put forward. Through the stress results of the dam body after reinforcement, the optimal reinforcement scheme and implementation conditions were obtained. The results show that the local reinforcement schemes such as thickening reinforcement and rib pier reinforcement on the downstream side of the dam can significantly reduce the stress in the reinforcement area. However, under the initial reinforcement condition(the 139 m upstream water level before reinforcement), none of the schemes can meet the tensile stress control standard. The maximum tensile stress is related to the type of reinforcement and the upstream water level before reinforcement. The sensitivity analysis of the upstream water level before reinforcement shows that the low water level is beneficial to reduce the tensile stress at the dam heel, but it is easy to lead to a large tensile stress near the top of the reinforcement area. Under the condition of scheme 2, when the upstream water level is between 130 m and 134 m before reinforcement control, it can meet the control standard of tensile stress, which is the recommended scheme in this paper.