胶凝砂砾石坝剖面设计研究

Study on the Design of the Section Type of CSG Dam

结合胶凝砂砾石材料力学特性及坝体剖面设计理论,研究胶凝砂砾石坝的剖面形式及相应的控制标准。按土石坝设计理论：当胶凝砂砾石材料抗压强度低于3 MPa时,坝体剖面形式属于土石坝断面形式,应按土石坝设计理论进行设计;当材料抗压强度大于6 MPa时,坝体剖面形式属于重力坝断面形式,应按重力坝设计理论进行设计;抗压强度为3-6 MPa时,剖面设计既要考虑坝体整体稳定性、坝体应力状况,又要考虑坝坡的自身稳定及坝体局部抗剪强度。按重力坝设计理论：当胶凝砂砾石材料抗剪强度指标足够大时,需控制坝踵处不出现拉应力,最经济剖面为直角梯形;随着坝体抗剪强度指标的降低,最经济剖面逐步由直角梯形向对称梯形过渡,此时稳定安全系数和坝踵拉应力都需要控制;当胶凝砂砾石材料抗剪强度指标过低时,采用对称梯形剖面,此时坝体不会产生拉压力,需控制坝体整体稳定安全系数满足规范要求。

Based on the mechanical properties of CSG material and dam profile design theory, the profile type and the corresponding control standard of the CSG dam were studied. According to the design theory of earth rock dam： when the compressive strength of the CSG material is lower than 3 MPa, the dam section belongs to the section of the earth rock dam, which should be designed according to the design theory of the earth rock dam; when the compressive strength of the material is greater than 6 MPa, the section of the dam section belongs to the section of the gravity dam, which should be designed according to the design theory of gravity dam; when the compressive strength is between 3-6 MPa, the section design should consider not only the overall stability of the dam and the stress state of the dam, but also the stability of the dam slope and the local shear strength of the dam. According to the design theory of gravity dam： when the CSG materials anti shear strength index is high enough, it needs to control the upstream dam heel for preventing tensile stress, the most economic section is a right angle trapezoid; with the decrease of dam shear strength index, the economic section transits gradually from the right angled trapezoid to symmetrical trapezoid, it needs to control the stability safety factor and the tensile stress of the upstream dam heel; when the shear strength index of CSG is too low, the dam will not appear tensile stress with the symmetric trapezoidal profile and the stability safety factor of the dam can be controlled to meet the requirements of the standard.