ANALYSIS ON VARIATIONS OF DISPLACEMENT RATES UNDER INFLUENCES OF RAINFALL AND EXCAVATION—TAKING RIGHT BANK SLOPE OF GAOBEI KEY WATER CONTROL PROJECT AS CASE STUDY

How to use the time schedule in case of heavy precipitation and undertaking intensive excavation of the retaining wall pit, and then upward backfilling the slope as permanent reinforcement, is the priority countermeasure in the tail canal project. The information construction depends on the analysis results of the deformation process and displacement vector relationship, from the primary landslide and then transformed to the cut slope. This paper takes the right bank slope of Gaobei Key Water Control Project as an example. It analyzes the monitoring data during the excavation of retaining wall foundation pit of the tail canal, It obtains the three-dimensional vector space-time variation relations of 55 monitoring points. It reveals the mechanism of clockwise compression-shearing consolidation drainage failure in the process of slope deformation. It bases on the correlation of precipitation data and obtains the corresponding relationship between slope deformation and precipitation, as well as excavation in 4 different stages. The statistical relationship between the average daily displacement rate and the daily precipitation is approximately as v=103.45ln(p)-82.821. The paper infers that during the period of non-strong rainfall, the displacement rate caused by excavation of the slope foot reached 200mm ·d^-1, which is the key parameter of information construction. The above failure modes and monitoring analysis results provide a basis for the information construction of retaining wall beside the tail canal. As a result the landslide was mitigated and cut slope was reinforced as designed in a rainy season.