缓倾外层状结构边坡变形破坏模式及支护对策研究

CASE BASED ANALYSIS OF FAILURE MODES AND UPGRADING MEASURES FOR GENTLE CUT ROCK SLOPES WITH INCLINED LAYER STRUCTURE

高速公路开挖形成越来越多的工程边坡。缓倾外层状结构边坡作为一种典型的岩质边坡,一般情况下整体稳定性较好,但在特定的结构面组合状况下,开挖后也可能产生整体变形破坏。本文以软弱结构面和长大裂隙发育的公路工程边坡为例,通过岩体结构及边坡一定范围内已有边坡破坏现象的调查研究,采用工程地质类比和三维离散元法综合分析边坡变形破坏模式,并针对变形破坏模式的特点,提出支护对策。研究结果表明,结构面贯通坡体形成切割块体的后缘和侧缘边界时,缓倾外层状结构边坡可沿层面产生滑移-拉裂变形,若滑面与临空面具有一定夹角,边坡的变形可表现为旋转式滑移-拉裂;结构面组合控制的缓倾外层状结构岩质边坡稳定性受坡体中下部的关键块体控制,一旦关键块体失稳,将引起上部块体的连锁失稳,此类边坡变形控制的重点是对关键块体分布区域进行强支护;支护工程实施后的变形监测结果表明,基于变形破坏模式分析的边坡支护方案保证了边坡施工和运营过程中的安全。

The development of economy in China has resulted in more and more infrastructural constructions such as highways in mountainous areas. As a result, more and more man - made slopes are excavated. The stabilities of rock cut slopes with gentle inclined layer structure they may generate deformation and damage under highway slopes with weak discontinuities and long are generally adequate under normal circumstances. However, particular combination of discontinuities. This paper uses 1 cut joints as an example to study the failure modes and supporting measures. The study is based on investigation of rock mass structure and analysis of slope deformation phenomenon over a certain scope of the studied area. The paper further adopts a three dimension discrete element method to analyze the failure modes of the cut rock slope. The numerical result is in accordance with the result of engineering geological analog. At last, the supporting measures are advanced in close combination with the characteristics of the slope failure mode. The study results indicate that the slipping and cracking deformation can be generated in gentle inclined layered slopes when the discontinuities can form ever, there is one special case. The rotary type slipping an angle between the trends of sliding surface and slope trailing edge and lateral boundary and cracking deformation can be in the slope body. Howgenerated when there is surface. It is also found that the stabilities of gentle inclined layered slopes are controlled by the key blocks located in the lower - middle part of the slope. The key block failure can cause a chain type of failures of the upper blocks. Consequently, the deformation controlling measures should focus on the region where the key blocks locate. Supporting measures of the cut rock slope established based on the failure mode analysis can guarantee the safety under both construction and operation conditions, which are shown by monitored results.