大坝与抗力山体联合抗滑计算方法的初步探讨

A Simplified Solution to the Slide-resistant Stability of Dam Jointed with Mountain Rock: Based on Material Mechanics

与抗力山体联合作用是大坝抗滑稳定常用的措施,但由于受力复杂,通常采用有限元等方法进行安全评价。出于工程实用的需要,采用材料力学方法对大坝与下游抗力山体联合作用的受力状况进行分析,并以重力坝坝基刚体极限平衡抗滑稳定求解方法为基础,提出坝基抗滑稳定计算简易方法,并推导出相关公式。通过与有限元分析方法进行对比分析,认为材料力学方法的基本假定较为合理。结合典型算例和工程实例,进行抗滑稳定计算。结果表明:对于该工程实例,在正常工况下,不考虑下游山体的抵抗作用及考虑该作用时,坝体抗滑稳定系数分别为2.97和4.87;在地震工况下,这2个抗滑稳定系数分别2.24和3.89;考虑抗力山体作用后,2种工况安全系数均大幅度提高。作为一种探索复杂受力状况下坝基稳定问题的方法,其物理力学意义清晰,计算过程简便,对于解决工程实际问题具有便捷性和实用性,其求解思路也可供其它类似工程的大坝抗滑稳定计算参考。

To joint a dam with resistant mountain rock is a common measure against sliding. Due to complicated forces in this case,finite element method is usually adopted in the safety evaluation. In this research,we applied mechanics of material to analyse the forces between the dam and the downstream mountain rock mass. Moreover,we put forward a simplified method of calculating the slide-resistant stability of dam foundation and deduced the formula based on rigid-body limit equilibrium solution for gravity dam foundation. By comparing it with finite element method,we conclude that the basic assumption of the present method based on material mechanics is reasonable.Furthermore we applied this method to the calculation of a typical calculation example and an engineering example.Results show that as for the engineering example,the anti-sliding safety factor is 4. 87 and 2. 97 respectively in the presence and in the absence of mountain rock resistance under normal working condition,and 3. 89 and 2. 24 under seismic condition. The safety factors in both conditions are greatly improved in the presence of mountain rock resistance. As a preliminary exploration on dam foundation with complex forces,the method has clear physical and mechanical meaning,and convenient calculation process.