舟曲特大山洪泥石流堰塞坝稳定性分析

Zhouqu Catastrophic Mudslide Barrier Dam Stability Analysis

通过现场工程勘察、监测和试验等方法,查明舟曲泥石流堰塞坝体的物质组成、来源和形态。利用FLAC3D软件分析了坝体在不同水位、不同坡度、不同含水量、不同物质组成和地震工况下的位移场、应力场和安全系数,结果表明:坝体应力和位移随堰塞湖水位的升高而增大,但增幅较小;坝体稳定安全系数随堰塞湖水位的升高而降低,随着坝体材料含水量的减小坝体最大应力值增大,但增加范围较小,同时最大位移值减小,坝体稳定性增强;在Ⅷ度地震作用下,其应力和位移分布特征将发生巨大变化,应力和位移增加显著,位移值约为无震时的10倍。采用正交试验方法,研究了该泥石流堰塞坝体不同物质组成的物理力学性质对坝体位移、应力特征和安全系数的影响,结果表明:弹性模量对坝体位移影响显著,而黏聚力和内摩擦角对坝体位移影响较小;内摩擦角对边坡安全系数影响显著,黏聚力次之,而重度影响则明显小于内摩擦角和黏聚力。

It had a full understanding of the material composition, source and form of landslide barrier bar by site investigation, survey, engineering monitoring, test and other engineering methods. It calculated the dam＇ s displacement and stress fields and safety factors under different water lev- els, slope angle, water content, material composition and the earthquake working conditions with FLAC3D. The results indicate that stress and the displacement increases with the increase of the lake water level, but the added value of amplitude is small. Safety factor of the dam decreases with the increase of the water level of the barrier lake ; with the decrease of water content, maximum stress value increases, but the increasing range is small, ma^ximum displacement decrease at the same time, the dam body stability is increased. Under VIII degree earthquake, it changes greatly in its stress and displacement distribution, stress and displacement increase significantly; the displacement value is about 10 times of seismic. Orthog- onal test is used to study the influence of material composition on stress, displacement characteristics and safety factor. The results show that the in- fluence of elastic modulus on dam displacement is remarkable, while internal friction angle and cohesion are smaller. The order of the influence on slope safety factor is internal friction angle, cohesion and unit weight.