秦巴山区某填方边坡加筋土挡墙破坏机理研究

Study on Failure Mechanism of Reinforced Earth Retaining Wall of a Fill Slope in Qinling-Bashan Mountain Area

针对秦巴山区某填方边坡路基加筋土挡墙垮塌导致的坡顶道路围栏垮塌、坡脚房屋受损等问题。现场调查查明了加筋土挡墙的破坏特征,结合数值模拟对加筋土挡墙破坏的诱发因素和形成过程进行了综合分析。结果表明:加筋土挡墙的破坏特征主要为:面板发生大面积垮塌,其后的加筋填料仍保持较好的整体稳定性;加筋土挡墙面板垮塌破坏主要是由于填方边坡阻隔了原始排水通道,支挡结构中的“抗滑桩-挡土板-加筋土挡墙面板”形成相对隔水边界,连续降雨和居民生活用水入渗后无法及时排出,从而引起地下水位升高,静水压力增大所致。加筋土挡墙破坏的形成过程为:静水压力增加—底部面板拉筋连接破坏—中上部面板受力增大—面板整体破坏。

A reinforced earth retaining wall of a fill slope subgrade in Qinling-Bashan Mountains collapsed six years after its completion,resulting in the destruction of the road fence at the top of the slope and the damage of the houses at the foot of the slope.The failure characteristics of the reinforced earth retaining wall were found out through field investigations,and the inducing factors and formation process of the failure of the reinforced earth retaining wall were comprehensively analyzed combined with numerical simulations.The results show that the main failure characteristics of the reinforced earth retaining wall are the face slab collapses in a large area,and the reinforced filler behind the slab still maintains a good overall stability.The collapse of the reinforced earth retaining wall panel is mainly due to the fact that the fill slope blocks the original drainage channel,and the“anti-slide pile+retaining plate+reinforced earth retaining wall panel”in the retaining structure forms a relatively impermeable boundary,while the water infiltrated from continuous rainfall and domestic water cannot be drainaged in time,resulting in the rise of the groundwater level and of hydrostatic pressure.The failure process of the reinforced earth retaining wall is as follows:increasement of hydrostatic pressure,failure of bottom panel tie bar connection,increasement of upper and middle panel stress and overall failure of panel.