坝区岩体的剪切蠕变经验方程及参数数值反演

岩体的剪切蠕变特性是影响坝区边坡岩体变形与长期稳定性的重要因素之一。利用现场剪切蠕变试验数据回归拟合得到了坝区“硬、脆、碎”辉绿岩脉的剪切蠕变经验方程,并由最小二乘法得到了剪切蠕变经验方程的拟合参数;提出了可以真实模拟现场剪切蠕变试验过程以及岩体实际地层分布情况的蠕变参数数值反演分析方法。通过对比分析可知,回归拟合变形值及数值反演计算变形值均与试验变形值比较接近,最大误差均未超过8％,表明剪切蠕变经验方程能有效反映坝区岩体的剪切蠕变变形特性,且建立的剪切蠕变数值模型也是合理可靠的,这为深入认识和了解坝区辉绿岩脉在不同应力水平下的剪切蠕变力学特性提供了重要的试验和理论依据,也为坝基边坡工程稳定性分析和设计提供了技术参数保证。

Shear creep empirical equations and creep parameter numerical inversion for dam zone rock mass

Shear creep characteristics is one of the important factors of deformation and long term stability of slope rock mass. By regression fitting in situ shear creep test data, a shear creep empirical equation of “hard brittle tatter” diabase dikes was obtained. Using the least square method, the fitting parameters of empirical equation was gained. A creep parameter numerical inversion method was presented, which could simulate in-situ shear creep test process and the distribution of rock stratum. Comparative analysis indicated that the fitting curve and numerical curve could both reflect the test curve well and the maximum error was only 8％. So, the shear creep empirical equations could effectively reveal the shear creep characteristics of dam zone rock mass, and the shear creep numerical model was also reasonable and reliable. The inversion analysis method could help to understand shear creep characteristics under different stress levels of diabasic dike at dam site of Dagangshan Hydropower Station. This method could also provide important technical parameters guarantee for stability analysis and design of slope in dam zone.