泥石流流速横向分布特征与防治工程结构优化  

Research on lateral distribution features of debris flow velocity and structural optimization of prevention and control works

作　　者：徐林荣[1] 韩征[1,2] 苏志满[1,3] 吴强[1] 

机构地区：[1]中南大学土木工程学院,长沙410004 [2]九州大学工学府 [3]中国科学院成都山地灾害与环境研究所,成都610041

出　　处：《岩土力学》2012年第12期3715-3720,3728,共7页Rock and Soil Mechanics

基　　金：国家自然科学基金(No.41272376);交通部西部交通建设科技项目(No.200831800087);四川省交通厅科技项目(No.2006A024-582)

摘　　要：以往研究表明,泥石流流速在沟道横断面上分布不均,但目前尚无理论依据,国内现行相关规范暂时建议在泥石流拦挡坝、排导槽等防治工程设计时,流速、荷载按均布考虑,这与实际的受荷情况有所差别,从而导致防治工程局部稳定性偏小,极易发生工程失效。为此,基于冲淤平衡原理、流体均质假设及沟道横断面形状的合理简化,结合雨洪修正法与形态断面法相关原理,演绎了沟道横断面任意位置流速计算公式的推导过程,并获取了泥石流流速的横向分布的非线性特征。通过四川省地震灾区理县甲司口沟泥石流防治工程的实例分析,发现横向上泥石流的中泓线流速与两侧流速相差达到300%。据此对拦砂坝进行了结构优化设计,在确保功能的前提下,提高了坝体稳定性系数约20%,节约了工程造价约5%。Former researches indicate that the distribution of debris flow velocity is laterally asymmetrical. Due to a lack of a theoretical basis on it, velocity and load have to be calculated on uniform state advised by current design regulations when the debris flow dam and drainage canal are designed. It is different to the practical status, which may lead to the engineering failure due to the poor partial stability. Therefore, based on deposition-erosion equilibrium, isotropic fluid hypothesis and reasonable simplification for debris flow＇s gully cross-section, the nonlinearity features of debris flow velocity＇s lateral distribution was proposed by deducting the deducing process of the velocity calculation formula at any cross-section. With the instance analysis of debris flow mitigation and control work at earthquake-stricken areas in Lixian, Sichuan province, we found that the debris flow velocity at channel line is triple the one at either side, and conducted the structural optimization design for debris dam on the premise of ensuring its function, reducing the risk of the dam break and instability of debris dam, which would rise the dam stability coefficient by 20%, and save the engineering cost by 5%.

关 键 词：泥石流 流速 荷载 横向分布 拦砂坝结构优化 

分 类 号：TV8[水利工程—水利水电工程]