土钉支护开挖影响面及其在土钉力计算中的应用

EXCAVATION INFLUENTIAL SURFACE OF SOIL NAILING AND ITS APPLICATION IN ESTIMATING THE NAIL TENSILE FORCES

结合土钉支护的施工特点和受力规律,定义施工阶段土体开挖时滑动趋势最大的面为开挖影响面,定义以开挖影响面为边界的土块体作用在支护体系上由土钉承担的力为开挖土压力。通过开挖阶段相邻两步的开挖土压力求出土钉支护因开挖而产生的不平衡力,同时考虑保持土体稳定所需要的抗滑力后可得到开挖阶段土钉轴力。首先分析开挖影响面和开挖土压力及其影响因素,然后给出开挖阶段计算土钉轴力的具体方法,并给出与法国CLOUTERRE项目1号墙足尺试验中土钉力测试值的比较。

Based on the constructional feature of soil nailing, concepts defining a family of EIS Excavation Influential Surface （the most likely slip surface when the latest excavation surface remains temporarily unsupported and the nails are not yet installed） and EEP Excavation Earth Pressure （the earth pressure that the soil body from the concrete face to the EIS act on the retaining structure） are proposed. The EEP of （il）^th excavation phase subtracted from the ones of the ith phase gives the unbalanced forces during the i^th construction step. The unbalanced forces will be balanced by the nails. And taking into consideration of the nails＇ contribution to the slope stability, nail tensile forces will be induced. This paper focuses on the EIS and the method to calculate the soil nail forces where the simple linear wedge EIS is used. By means of the method, we can estimate the location and magnitude of the maximum nail tensile forces during construction. The calculated nail forces for Experiment 1 of CLOUTERRE Research Project by this method agree fairly well with the experiment data.