水位变化对砌石坡岸遗址稳定性的影响

水库、河流等水位的变化是影响坡岸稳定性的重要因素,特别对于遗址中的河堤、护坡等,在水位发生变化时,极易发生崩塌、滑移等事故,严重威胁了文物及人员财产安全.针对贵州镇远青龙洞古建筑群中湘黔古驿道进行流固耦合数值模拟研究,分析了不同水位涨落工况下古驿道堡坎的位移及安全系数的变化;并结合现场情况进行了对比研究.结果表明:堡坎的最大位移处于坡岸的中下部区域,与现场鼓胀病害位置一致;常水位状态下,古驿道处于基本稳定状态,但安全储备不足,水位上升阶段,浮力作用造成整个滑坡体的抵抗力变小、稳定性降低.当水位急剧下降时,坡岸中产生渗透水压力,造成稳定性降低,容易诱发崩塌,7m高坡岸在水位4～5m处;6m高坡岸在水位1m和3.5～5m处,安全系数较低,容易发生垮塌事故,与之前的垮塌情况相吻合.研究可为此类砌石坡岸遗址的保护提供参考,也为相关加固工程提供理论依据.

Study on the influence of water level fluctuations on the stability of ancient masonry bank

Water levels change is an important factor affecting the stability of the slope. Especially for the ruins of the embankment, slope protection, etc., it is very easy to collapse and other accidents when the water level changes. Not only destroyed the original appearance of the ancient sites, but also threat to the safety of staff and tourists. In this paper, a numerical simulation of Xiangqian ancient post road in Qinglongdong ancient buildings, Zhenyuan, Guizhou Province is carried out. The displacement and safety factor of ancient post road pit are analyzed under different water level conditions, which combined with the site condition. The results show that the maximum displacement of the castle is in the middle and lower area of the slope, which is consistent with the location of the bulging disease. In the normal water level, the ancient post road is in a stable state, but the safety reserve is insufficient. During the rising of water level, buoyancy force reduces the resistance and stability. When water levels fell sharply, the seepage water pressure in the bank, which reduces the stability, easy to induce collapse. With the water supply from the upstream hydropower station and the irrigation, the stability of the ancient post road is greatly reduced, especially in the water level of 4 to 5m for 7m high bank, 1m and 3.5 to 5.0m for 6m high bank, which in conformity with the collapse before. The calculation results can provide reference for the protection of such masonry slope site, but also for the relevant reinforcement theory to provide theoretical basis.