Soft Rock High Slope Deformation Mechanism And Strengthening Project Research

Soft rock widely distributes in the world, which is one of the most important controlling factors in slope engineering. There are many road cutting slopes along Jiang-Zhu (Jiangmen City to Zhuhai City) Expressway in Guangdong Province with typical characteristics of soft rock slope, such as weak lithology, serious cutting of structure plane. These soft rock cutting slopes were difficult to cut and reinforced. This thesis relies on the soft rock cutting slope engineering along Jiang-Zhu Expressway. A series of research works were conducted concerning about these slope engineering, including field investigations, rock parameters testing, estimation of stability of rock structure, and numerical analysis of slope stability. Deformation mechanism and reinforcement scheme of soft rock high slope were discussed based on these work. Results were showed as followings:According to the results of field investigation, slope K17+390-K17+724.3and slope K17+970～K18+230are both belong to soft rock high slope, however, their combination situations of rock structure plane are different. As a result, toppling failure would occur in slope K17+390～K17+724.3, while in slope K17+970～K18+230, it may turn up consequent layer sliding.According to the results of monitoring of slope deformation, the stability of slope K17+390～K17+724.3was affected obviously by rainfall and blasting construction, however, the slope remained stable all the time. It was shown that anchors system in the toe of slope and the construction measures of gradually excavating and reinforcing were good for the stability of cutting slope.According to the results of numerical analysis, comparing with the construction approach of gradually evacuation and reinforcement, fully evacuation and reinforcement was resulted in a similar factor of safety after the construction, which an obviously lower factor of safety appeared in the most dangerous stage. If it happened to come across a heavy rainfall, it may result in slope failure.Results of numerical analysis in optimization design of anchors showed that factor of safety change obviously when the extent of increase in the length of anchor was large enough. When the total length of anchors was kept the same, anchoring scheme A with short length in higher slope layer and long length in lower slope layer was resulted in a better stability of slope in normal situation, comparing with anchoring scheme B with long length in higher slope layer and short length in lower slope layer.