人类活动影响高速公路滑坡的发灾机理和致灾模式研究--以余家海滑坡成因机理为例

Influence of Human Activities on Development Mechanism and Disaster Mode of Landslide of Highway:Taking the formation mechanism of Yujiahai Landslide as an example

高速公路桥梁横跨滑坡体导致公路安全运营问题突出,经济损失严重。以余家海互通立交BK0+601桥滑坡体为例,通过现场调研和钻孔调查,分析该类型滑坡的发灾机理和致灾模式,计算在不同工况下边坡稳定性,提出该类型滑坡的针对性治理方案。结果表明,导致该滑坡发灾的主要因素为不合理的堆载与边坡前缘开挖后支护不及时的人类活动,在降雨的耦合作用下导致滑坡发生。揭示该滑坡致灾机理,是由于前缘水库清淤导致临空面增加,在滑坡的牵引-拉裂作用导致承灾体受损。降雨与库水位波动耦合加剧滑坡的灾变,使桥墩发生位移,威胁行车安全。致灾模式包括排水槽损坏、桥墩基础拉裂以及上部结构破坏和堵河次生灾害。通过稳定性计算与分析表明该滑坡为欠稳定,未来在降雨作用下会出现局部滑动。提出格宾挡墙与护坦的针对性治理措施,能防止库水波动影响,起到拦挡作用。

The highway bridge crossing the landslide leads to highway safety operation problems and serious economic losses.The landslide of BK0+601 bridge of Yujiahai was adopted as an example.Field investigation and borehole analysis are the main means to analyze the development mechanism and disaster mode of landslide.A treatment plan is proposed for this landslide.The results show that increase of accumulation loading of landslides and cutting slope in the front edge of landslide reduced the stability of the slope,which leaded to the occurrence of disaster under the coupled of rainfall.Engineering facilities were damaged by pulling function of landslide caused by the toe cutting due to reservoir dredging.And disaster modes of landslide were revealed,including the damage of drainage channel,the tension crack of pier foundation,the damage of superstructure and the river-blocking event.The stability calculation were showed that the landslide was in an unstable state.Local sliding would occur under rainfall in the future.The suggestions of targeted treatment and bridge reinforcement treatment are put forward.