贵州冬瓜山大桥区域堆积体稳定性评价

Stability Evaluation of Accumulation in Dongguashan Bridge Area in Guizhou

为了对贵州冬瓜山大桥区域堆积体稳定性进行初步分析,为桥梁选址提供技术支持。通过详细的工程地质调查、钻探等手段,查明冬瓜山大桥区域堆积体分为D1、D2、D3三个区域,初步判定D1、D2区堆积体处于变形阶段、D3区堆积体稳定。采用极限平衡分析方法与有限差分数值分析对堆积体稳定性、岩土体应力特征进行分析,结果表明:1)D1区堆积体前缘在暴雨工况下处于基本稳定状态,堆积体沿基岩面整体滑动可能性较小,浅层潜在滑动趋势显著;2)D2区堆积体浅层滑动体在天然与暴雨工况下均不稳定,深层滑动体在两种工况下均处于稳定状态,D2区堆积体整体处于稳定状态。D2区堆积体浅层粉质黏土滑移趋势显著,沿深层潜在滑动面和基岩面整体滑动的可能性小;3)D3区堆积体处于稳定状态,堆积体沿着基岩面整体滑动的可能性较小。建议对D1区潜在前缘深层滑动体进行加固防护;对D2区浅层滑动体进行防护设计;对D3区采用加强堆积体范围内截排水措施和变形观测等综合防治措施。

In order to make a preliminary analysis of the stability of the accumulation in the Dongguashan Bridge area,this paper analyzed the stability of the accumulation and the stress-strain characteristics of the rock and soil mass by means of detailed engineering geological investigation and drilling,combined with the limit equilibrium and numerical simulation methods.We suggest that the accumulation in the Dongguashan Bridge area can be divided into three areas:D1,D2 and D3.Moreover,we determine that the accumulation in D1 and D2 areas is in the deformation stage and the accumulation in D3 area is stable.We used the ultimate equilibrium analysis method and finite difference numerical analysis to analyze the stability of the accumulation and the stress characteristics of rock and soil mass.The results of limit equilibrium analysis showed that the front edge of the accumulation in the D1 zone is basically stable under heavy rainfall conditions.The accumulation in zone D3 is in a stable state.The shallow sliding body of the accumulation body in the D2 zone was unstable under both natural and rainstorm conditions,whereas the deep sliding body was in a stable state under both working conditions and the accumulation body in the D2 area was in a stable state as a whole.The results of the overall finite difference numerical analysis showed that the overall sliding possibility of the accumulation along the bedrock surface in the D1 area was small,whereas the potential sliding trend of the shallow layer was significant.The slip trend of shallow silty clay accumulation in D2 zone was significant,whereas the possibility of sliding along the deep potential sliding surface and bedrock surface as a whole was small.It is less likely that the D2 accumulation would slide along the bedrock plane as a whole.The qualitative and quantitative analysis results of the stability of the accumulation are consistent and can be verified.We suggest that the deep sliding body of the potential leading edge of the D1 zone should be strengthened and protected.The protection design of the shallow sliding body in the D2 zone was carried out.Comprehensive prevention and control measures such as strengthening the interception and drainage measures within the accumulation area and deformation observation were adopted for the D3 area.