高面板砂砾石坝堆石料力学变形特性及坝体分区研究

Mechanical deformation characteristics of rockfill and dam body zoning of high concrete face gravel dam

随着高混凝土面板砂砾石坝坝高的突破,坝体内部高应力区和坝坡、坝顶低应力区的应力差别增大,而不同应力条件下砂砾石料和块石料的力学特性存在较大差异,将影响着坝体分区及变形安全。开展砂砾石料和块石料三轴力学试验,研究不同应力条件对其力学变形特性的影响;在此基础上根据坝体应力分布特征,研究高混凝土面板砂砾石坝坝体分区。研究表明,在低围压条件下,块石料的模量系数大于砂砾石料;随着围压增加到一定程度,块石料颗粒破碎导致模量系数大幅降低,远小于砂砾石料的模量系数;为充分利用两种堆石料的力学变形特性,加强高面板砂砾石坝坝体变形控制,坝体内高、低应力区应分别采用砂砾石料和块石料填筑,提出一种基于坝体应力分布特征的坝体分区准则和优化调整方法;最终推荐一种块石料半包砂砾石料的坝体分区型式,提高了高混凝土面板砂砾石坝的综合安全性。

With the height breakthrough of the high concrete face gravel dam,the stress difference between the high stress zone inside the dam body and the low stress zone on the dam slope and top increases.The mechanical properties of gravel and block stone under different stress conditions are quite different,which directly affects the partition and deformation safety of dam body.The triaxial mechanical tests are carried out to study the influences of stress conditions on the mechanical and deformation characteristics of gravel and block materials.On this basis,according to the stress distribution characteristics of the dam body,the zoning criteria for high concrete face gravel dams are studied.The results show that the modulus coefficient of block is greater than that of gravel under low confining pressure.With the increase of the confining pressure to a certain extent,the modulus coefficient of block materials decreases greatly,while that of gravel materials is larger.In order to take advantage of the mechanical properties of the two materials and strengthen the deformation control of the dam body,the zoning criteria and the optimization adjustment method based on the stress distribution characteristics of the dam body are proposed.The high-and low-stress areas of the dam are filled with gravel and block stone,respectively.Finally,a type of partition type of the dam body with block stone and half-clad gravel stone is recommended,which improves the comprehensive safety of the high concrete face gravel dam.