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塑性混凝土材料广泛用于水工建筑物基础的防渗处理中,尤其在高土石围堰防渗墙中得到了较大规模的应用,但其材料试验方法及结构计算中所采用的安全评判标准尚无相应的规程规范。以往常采用土石料的三轴压缩试验方法获取塑性混凝土的变形及强度参数,并采用应力水平衡量围堰塑性混凝土防渗墙的安全性。但应力水平由土体三轴压缩状态引入,其多用于适应莫尔库仑摩擦强度理论的散粒体材料安全状态的评判,对于应力状态复杂的深防渗墙混凝土材料宜通过混凝土强度理论进行安全复核。通过对高土石围堰防渗墙应力状态的分析,引入包含混凝土多轴强度的安全度准则,以白鹤滩大坝上游高土石围堰防渗墙为例,利用三维有限元分析,比较基于应力水平与安全度准则评价防渗墙安全性的差异,表明安全度准则较应力水平能更为灵敏地反映防渗墙安全性态,认为在三轴受压状态下应力水平尚能较好的反映防渗墙的安全状态,但在拉应力较明显的条件下宜采用基于混凝土多轴强度的安全度准则进行复核。
Plastic concrete materials are widely used in the seepage control foundation of hydraulic structures, especially in high earth cofferdam impervious wall has been larger scale applications, but the material testing methods and structural safety evaluation criteria used in the calculation There is no corresponding code of practice. In the past, the deformation and strength parameters of plastic concrete were obtained by triaxial compression test of soil and stone, and the safety of plastic concrete cutoff wall of cofferdam was measured by stress level. However, the stress level is introduced by the triaxial compression state of the soil, which is mostly used to judge the safety status of the granular material which is adapted to the theory of the Mohr-Coulomb friction strength. For the deep impervious concrete wall with complicated stress state, the concrete strength theory should be safe Review. Based on the analysis of the stress state of impervious wall of high earth cofferdam, the safety criterion including the multiaxial strength of concrete is introduced. Taking the high earth cofferdam impervious wall upstream of Baihetan Dam as an example, three - dimensional finite element analysis is used to compare the stress - Level and safety criteria evaluation of impermeable wall safety differences, indicating that the safety criteria than the stress level can more sensitively reflect the impermeable wall safety state, that the stress level in the triaxial compression state can still better reflect Impermeable wall security status, but in the more obvious tensile stress conditions should be based on the safety of concrete multi-axis strength criteria for review.