黄土细沟流跌坑的形成与作用机理  

Stability Analysis on Surrounding Rock Mass in Underground Caverns Based on Discrete Element Simulation and Microseismic Monitoring

作　　者：董旭[1,2] 张宽地 王光谦[4] 王俊杰[1] 马小玲[1] 

机构地区：[1]西北农林科技大学水利与建筑工程学院,陕西杨凌712100 [2]中国电建集团华东勘测设计研究院有限公司,浙江杭州310000 [3]中国科学院水利部水土保持研究所黄土高原土壤侵蚀与旱地农业国家重点实验室,陕西杨陵712100 [4]清华大学水沙科学与水利水电工程国家重点实验室,北京100084

出　　处：《四川大学学报（工程科学版）》2016年第5期1-8,共8页Journal of Sichuan University (Engineering Science Edition)

基　　金：国家自然科学基金资助项目（51579214;51209222;41001159）;国家重点基础研究发展计划资助项目（2015CB040441）;黄土高原土壤侵蚀与旱地农业国家重点实验室开放基金资助项目（A314021402 - 1619）;流域水循环模拟与调控国家重点实验室开放基金资助项目（IWHR - SKL - 2014）;中央高校基本科研业务费专项资金资助项目（Z109021564）

摘　　要：跌坑是细沟侵蚀过程中形成的一种床面形态,其是床面形态和水流流动相互作用的结果。借鉴下切型阶梯-深潭理论采用6种坡度（2°、4°、6°、8°、10°、12°）,5种流量（8、16、24、32、40L/min）完全组合冲刷试验,系统研究了黄土坡面细沟流跌坑形态发育过程及动力特性。结果表明：跌坑平均深度随坡度的增加而增加,跌坑平均间距与跌坑平均深度的比值随坡度的增加而减小,表明跌坑随坡度的增加发育越加成熟,且流量对两者影响均较少;跌坑发育系数随坡度的增加而增大,其值介于1.01和1.14之间,与细沟阻力系数呈正势变化,表明随着跌坑发育越显著,水流阻力越大,能量耗散越剧烈。相同坡度下,跌坑消能率随流量的增加呈线性减小趋势;而消能率随坡度和跌坑发育系数的增加呈幂函数增加关系,消能率范围在87.28%~98.58%之间,研究结果表明跌坑的发育及作用机制对细沟流流动特性及侵蚀产沙具有重要作用。Aiming at the stability problems of the surrounding rock mass in the underground caverns at the Houziyan hydropower station subject to excation, based on the discrete element theory, the numerical simulation of excavation of the underground powerhouse caverns was performed using PFC2D software. The influences of the controlling structural planes on surrounding rock mass deformation and failure were simulated, and the damage evolution law was reproduced. Moreover, a high-resolution microseismic monitoring system was adopted to real-time monitor and analyze the microseismic activity in deep underground caverns. Then the results of numerical simulation were compared with microseismic monitoring. The results showed that excavation damage zone of surrounding rock mass was closely related to faults, and the surrounding rock mass damaged regions obtained from numerical simulation was in good agreement with those revealed by microseismic monitoring. Therefore the approach of combining numerical simulation and microseismic monitoring was proven to be very promising for evaluating the excavation damage zones and predicting the potential instability of surrounding rock mass in the underground caverns subjected to excavation.

关 键 词：跌坑 阶梯-深潭 跌坑发育系数SP 消能率 

分 类 号：TU457[建筑科学—岩土工程]