【摘要】 在砂砾岩基础上修建拱坝,坝体的垂直方向和顺河向变形是否过大,是关系到拱坝安全甚至能否修建的重要因素。砂砾岩受力变形有两个特点:一是在较低应力条件下,仍有较大的不可恢复变形;二是不同应力条件下,岩石的切线变形模量不同。通过分析现场原位变形试验,构造出能够反应出砂砾岩受力变形特点的非线性本构模型,并应用到实际工程中,分析其对坝体变形、应力的影响,可为工程规划和设计提供一定的参考依据。更多还原

【Abstract】 As for the Wuyi Hydraulic Project on the Dina River in Xinjiang Uygur Autonomous Region of China, the study shows that an arch dam will have a larger economical advantage over an earth dam for the spillway;and drain holes can be emerged into the dam body. No more separate constructions such as floodway,which is a necessary part for earth dams,are required. However,another key issue appears in the determination of the possibility for building an arch dam on sandy gravel:the deformation of the dam in both vertical and horizontal directions;and the corresponding stress distribution in the some situations can exert a great threat to the arch dam safety. The stress-displacement relation of sandy gravel has the two features as follows:(1) the irrecoverable deformation cannot be ignored even in lower stress status;and (2) the tangent deformation modulus is varied under the different stress conditions. Some in-situ tests have been carried out in the adits at different elevations of the dam site;and a nonlinear constitutive model is derived analyzing the effect of stress on rock deformation moduli. This model is capable of simulating the stress-deformation relation;and it can be applied to the assistant in the project layout and design by considering the stress and deformation in the dam body. As an example,this nonlinear model is compared with the linear-elastic model in low stress status,which is corresponding to low mountains at both ends of the dam. It is found out that,by using the nonlinear model,the deformations reduce both in vertical direction and along river direction. However,little change is found in the stress along the dam axial direction. In this case,certain measures can be taken to improve the problem:enlarging the dam bottom locally,mounting concrete piers at both sides of the downstream dam abutment,and setting up artificial short joints and so on.更多还原