高原寒区冻融作用对水利工程基岩边坡稳定性影响分析

Analysis of the influences of freezing-thawing action on rock slope stability of water conservancy engineering in high cold areas

西藏属于青藏高原的主体部分,该区域具有气候寒冷、温差大、太阳辐射强等特征,因而在海拔4 000 m以上的地区冻融作用特别突出,并对工程边坡造成一定的影响.在已有的试验参数的基础上,采用有限差分法,以西藏某水利枢纽工程泄洪洞进水口边坡为例,计算分析了冻融作用对不同工况下边坡稳定性的影响.通过计算分析得到,冻融作用会导致边坡安全稳定系数有微小的下降,变化虽然不大,但是由于西藏高寒地区临界稳定边坡多,冻融作用导致边坡变形破坏的可能性较大,从而给工程造成损失和危害.因此,在施工过程中应该采取必要的措施,采用防冻融的材料,及时锚喷封闭边坡,防止大量降水或者地下水的侵入,有效减小冻融作用的影响是十分必要的.

The Tibet Autonomous Region is located in the main part of the Tibetan Plateau,where the climate is cold with large temperature difference,strong solar radiation and so on. In the region,freezing-thawing action is especially prominent above 4 000 m altitude and causes a certain influence on the slopes. In this paper,on the basis of experiment,the finite difference method is adopted; a key water conservancy project intake slope of spillway tunnel is taken as an example to analyze the influences of freezing and thawing on the stability of the slope under different conditions by calculation. Through calculation and analysis,it is found that there is a tiny decrease in stability coefficient of slope safety caused by freezing-thawing action. Although it is a little change,but because there are many critical stable slopes in the region,freezing-thawing action increases the possibility of slope deformation and damage and causes loss and damage to the project slopes. Therefore,in the construction process the necessary measures should be taken. It is very necessary to use anti freezing-thawing materials. Side slopes should be timely anchored and closed in order to prevent a large number of intrusive rain water or groundwater and effectively reducing the effects of freezing-thawing action.