摘要
应用基于栅格的瞬态降水入渗边坡稳定性模型TRIGRS(Transient Rainfall Infiltration and Gridbased Regional Slope-stability M odel),模拟四川省广元市2010年"7·23"特大暴雨过程对边坡稳定性的影响,探讨模型适用性。结合实际滑坡发生情况,检验广元市不同区域斜坡稳定性变化对降水的响应。为增加模拟过程的可靠度,采用地形指数推算土壤厚度及初始入渗率,配合中国1∶100万土壤及岩性分布图将研究区域分为3个分区,基于已有研究确定模拟所需水土参数。将研究分析所得的滑坡高危区域与实际发生滑坡的区域进行对比,结果显示,坡度较大的陡峭区域出现少量降雨失稳概率即出现明显上升,而坡度较缓区域需经历较长时间降水或短时较大降水,失稳概率才会有明显的升高。模拟结果与"7·23"降水过程中实际发生滑坡区域较为吻合。模型在较为陡峭的山地区域应用良好,在坡度较为平缓,人为干扰因素较多的城市区域存在一定误差。
The utility of Transient Rainfall Infiltration and Grid-based Regional Slope-stability Model （TRIGRS） in combination with the rainfall distribution data estimates for shallow, rainfall-induced landslides forecasting and response of rainfall are examined through model simulations of July 23th, 2010 heavy rainstorm event in Si- chuan, Guangyuan. The target domain is divided into three physical property zones according to the distinct soil sediment concentration. The topographic indices of TOPMODEL （Topography based Hydrological model） are applied to calculate the soil thickness distribution and steady, pre-storm infiltration rate of the study area. As- sumptions based on existing studies are used to estimate the simulation parameters. The cohesion and fraction an- gle values are taken based on actual physical conditions of each zone. The inputs of TRIGRS model includes the digital elevation model （DEM）, slope angle distribution, soil thickness distribution and flow direction distribu- tion of the study area, and time-varying rainfall. Combined with the simulation parameters, the TRIGRS model computed transient pore-pressure changes and attendant changes in the factor of safety （FS） due to rainfall infil- tration. The every 6 h slope-instability grids given by model results matched the every 6 h rainfall accumulation distribution, consistent with the actual landslide records, indicates that the preliminary assessment of slope-stabili- ty is available over large areas. The quantitative indices and results of receiver operating characteristic of the sim- ulation results indicated that the way of model simulating of the study area was valid for shallow landslide fore- casting. Comparing the results with the shallow landslide inventory map, more than 71. 1% consistency between predicted shallow landslide susceptibility and the inventory, despite the paucity of the input data. The simulation results has reasonable consistency despite some shallow landslides located in hilly area. Based on different types
作者
徐沅鑫
郭海燕
马振峰
XU Yuanxin;GUO Haiyan;MA Zhengfeng(Sichuan Climate Center, Chengdu 610072, Sichuan, China;Heavy Rain and Drought-Flood Disasters in Plateau and Basin Key Laboratory of Sichuan Province, Chengdu 610072, Siehuan, China)
出处
《高原气象》
CSCD
北大核心
2018年第3期815-825,共11页
Plateau Meteorology
基金
四川省科技支撑计划(15ZC0098)
高原与盆地旱涝灾害四川省重点实验室项目
