【作者】 梁照江；

【导师】 何江达；

【作者基本信息】 四川大学 ， 岩土工程， 2005， 硕士

【摘要】 引水式电站长有压引水系统中,为降低高压管道的水锤压力、减缓引水洞中的水锤效应和改善机组的运转条件,在引水道和高压管道的连接处一般都建有调压室,地下开挖而成的调压室称为调压井。近年来,随着水电开发的不断深入,一批地质条件复杂且开挖断面巨大的调压井相继开工建设,其施工期的围岩稳定性和运行期的结构安全性问题非常突出,已成为制约该类型水电工程建设周期、投资和安全的关键技术问题。调压井结构是由其周边围岩和支护结构两者共同组成,并相互作用的结构体系。传统的设计方法通常将支护结构及受力进行简化,通过计入山岩压力和弹性抗力方式反映围岩对支护结构的作用,忽视了调压井支护结构与围岩相互作用过程中的变形协调和内力调整,其计算结果不能完全准确反映调压井结构的受力状态,特别是对建筑在复杂地基上的结构复杂的调压井,用简化方法计算出的结果往往差别很大,不能真实反映调压井结构的工作特性。四川岷江姜射坝水电站调压井为阻抗式,采用埋藏式长廊型布置,开挖尺寸为122.4×9.3×58.8m(长×宽×高),围岩全部为碎裂结构的Ⅳ、Ⅴ类岩石;吉鱼水电站调压井为阻抗式,采用露顶圆筒型布置,开挖直径为37.5m,高度约51.0m,围岩为坡残积层和冰水堆积层组成的Ⅳ类岩石;桑坪水电站调压井为圆筒差动式,大井开挖直径34.0m,井筒高47.75m。本文结合上述三个不同型式调压井的地质地形条件和结构型式,运用三维非线性有限元法模拟调压井分层开挖分层喷锚支护过程,研究了调压井施工期的围岩稳定性和喷锚支护效果,提出了调压井分层开挖控制高度,并研究了施工期和运行期控制工况下调更多还原

【Abstract】 In the long pressure water diversion system of diversion-type powerstation, surge chamber usually is build on the joint of diversion tunnel and diversion water pressure pipe in order to reduce water hammer pressure , and minish the water hammer effect and improve the working conditions of hydraulic turbines. Surge chamber which is excavated underground is called surge tank. Recently, along with the development of hydraulic powerstations, a lot of surge tanks in large size in complex geology structure has been built one after another, and the problem of surrounding rock stability during construction stage and structure safety during commissioning date is extrusive, which has became the key problem of construction period ,investment and safety of this kind of hydropower project. Surge tank is made up of surrounding rock and concrete structures. Traditional method usually simplifies the supporting structures and force, and reflect the action surrounding rock acted on the concrete structures by means of reckon in rock stress and elastic resistance, which ignores the interaction between rock and concrete structures. So the results can not reflect the operating state of the surge tank. The result computed with traditional method always different from the results with FEM. Especially for those complex surge tanks which built on complicated bed, the results can not show the operating behavior truly. Sichuan Minjiang Jiangsheba surge tank is in impedance shape with 122.4m long,9.3m wide and 58.8m high, whose surrounding rock consistes of Ⅳ,Ⅴclass. Jiyu powerstation surge tank is impedance shape hybrid type with 51m high and the excavation diameter is 37.5m, and the surrounding rock is made up of eluvium and accumulative ice formation. Sangping surge tank is hybrid type with 47.75m high and the excavation diameter is 34m. According to geology, landform and concrete structures of these surge tanks, surrounding rock stability and reinforce effect are modified, the control height of excavation is limited, the operating state of the surge tank in construction stage and commissioning date are studied, the rule of the deformation and stress are opened out and the reinforcing result can be got by means of computing the stress and deformation. Lastly, the deformation and stress behavior computed by F.E.M. are compared with that of traditional method. The study shows that, on condition that the surge tank with bad geology condition excavated from top to bottom with concrete liner protect on time, the max. stress of surrounding rock appears on the excavation working condition. The control working condition of bar, bed and arc of surge tank is in running working condition. Surrounding rock plastic site appears at the top, upside and bottom of the well rock during the excavation period of the round surge tank.. However, plastic site appears at the top and upside of the boxed surge tank underground, and careful action should be adopted during the construction period. The stress and deformation of the surge tank structure are computed with 3D FEM in different working states,through which the working characteristics of the surge tank can be explicitly reflected . At the same time, according to the amount and distribution of the structure stress, the amount of reinforcing needed can be computed easily, which provides gist for the designer. For circular surge tank, the stress and deformation computed based on tradition method of liner are symmetrical around the well, which are different from the results by means of 3D FEM at the same position. However, both the stress and deformation are regular.更多还原