缓倾角顺层斜坡变形破坏机理探析

Analysis of Deformation Failure Mechanism of Gently Inclined Bedding Slope

研究目的:沪昆客专贵州西段沙坡特大桥4#~10#墩左侧为高陡边坡,属典型的缓倾角顺层边坡,勘察阶段定性为崩塌落石工点,施工中发现该工点的崩塌落石规模和工程危害远超过原先的认识。本文基于无人机航拍技术,通过综合勘察和地质分析,查明崩塌落石的成因和斜坡变形破坏模式,并制定出切实可行的工程措施。研究结论:(1)沙坡特大桥4#~10#墩左侧为缓倾角顺层高陡边坡,崩塌落石之所以严重,系因滑移-压致拉裂变形破坏;(2)该高陡边坡的整治范围,重点是距陡崖约35 m的贯通节理附近至崖壁间,按高度分段设防,采取清方、锚索(地梁)、喷锚网、主动防护网、锚索桩、防撞墙、截排水沟等措施进行综合整治是适宜的;(3)线路傍山选线,应远离高陡岸(边)坡,对上硬下软的缓倾角顺层高陡边坡更应引起足够重视,以避免大规模崩塌落石的危害;(4)无人机具有从上往下拍摄的优势,用于复杂艰险山区不良地质勘察,可以起到事半功倍的效果;(5)本研究成果用于沙坡特大桥4#~10#墩左侧高陡边坡的整治,对于铁路、公路高陡岸坡崩塌落石发育区的选线、勘察和设计具有借鉴意义。

Research purposes： The left high and steep slope of super major Shapo bridge 4^#-10^# pier section, which located in the Guizhou western part of Shanghai - Kunming passenger dedicated line, is a typical dip bedding high - steep slope, and was described as rockfall site in the investigation phase. However, during construction, the site was found that rockfall scale and engineering hazard far exceeds the original understanding. Based on the UAV aerial, and the comprehensive investigation and geological analysis, the causes of collapse and rockfall, slope deformation failure mode were found out, and the feasible engineering measures were formulated. Research conclusions： （ 1 ） On the left side of the Shapo super major bridge 4^#-10^# pier was bedding high - steep slope, with serious rockfall hazards, which was caused by gently inclined bedding slope slip - pressure -induced deformation and damage of crack. （2） The key governance scope of steep - high slope was in the range of 35 m from cliff wall. The measures of section protection, and suitable comprehensive improvement measures are adopted such as the unloading, anchorage （beam）, spray anchor net, active protection network, anchored anti -sliding pile, anti collision wall, cut - row ditch, etc. （ 3 ） Route selection near the side of mountion should be far from steep - high slope, and regard the steep - high slope with the characteristics of upper harder and lower soft inclined bedding for avoiding the large - scale rockfall hazards. （4） Using the UAV aerial with advantage of shooting from top to down can play a multiplier effect to survey unfavorable geological hazards of the complicated difficult mountainous areas. （5） The research conclusions can be used to the steep - high slope treatment of the Shapo super major bridge 4^# - 10^# pier, and provide reference to the alignment, survey and design of the development rockfall area of railway and expressway.