路基悬锚式挡土墙墙背土压力分布

Distribution of Soil Pressure on Back of Suspension Anchor Retaining Wall

路基悬锚式挡土墙是一种新型的挡土墙,其墙背土压力分布与常规挡土墙墙背土压力分布规律不同,不能套用现有的公式进行计算。根据其受力特点,结合项目研究的需要和依托工程的实际情况,确定了以墙高8,9,10 m这3种工况对路基悬锚式挡土墙的墙背受力情况及土压力分布情况进行现场试验和跟踪检测。通过实体工程的实测数据及其结构特点对悬锚式挡土墙的墙背土压力进行了分析,并与墙后土压力设计值及修正后的公式计算值进行了对比。结果表明:路基悬锚式挡土墙各测试点的墙背土压力随时间逐渐增大并趋于稳定,沿墙高呈3段式非线性分布;墙背土压力近似分布图形可以参照现有锚定板挡土墙的计算方法得出,但需进行修正,土压力系数宜取1.2~1.4;为提高挡土墙墙背的受力均匀性及挡墙的整体稳定性,第1层锚杆高度与底板的距离宜为挡墙建筑高度的1/3且距离底板不宜大于2.5 m,各锚杆层间高差宜为2.5~3 m;墙背最上层锚杆位置由于受土压力较小,因此最上层锚杆布设高度宜为距墙顶1/3高处,且适宜高度为2~3 m;悬锚式挡土墙的双层锚杆与锚定板型式建筑高度宜为6~10 m,3层锚杆与锚定板型式建筑高度宜为10~12 m。

Suspension anchor retaining wall is a new type of retaining wall. Due to the distribution of soil pressure on the back of the wall is different from that on the conventional retaining wall,the existing formula cannot be used to calculate it. According to its force characteristics,combining with the needs of the project research and the actual situation of the support project,determining the working conditions of the wall height as 8,9,10 m,the field test and the tracking test on the stress and the distribution of soil pressure on the back of suspended anchor retaining wall of subgrade are carried out. The soil pressure on the back of the suspended anchor retaining wall is analyzed by the measured data and the structural characteristics of practical project,which is compared with the design value and the value calculated by the improved formula. The result shows that(1) the soil pressure of the measuring points on the back of suspended anchor retaining wall of subgrade gradually increases with time and tends to stability,it shows 3-stage nonlinear distribution along the wall height;(2) the approximate distribution figure of the soil pressure on the wall back can be obtained referring to the calculation method of existing anchor plate retaining wall,but it must be modified,and the soil pressure coefficient should be 1.2-1.4;(3) to improve the force uniformity of the back of the retaining wall and the overall stability of the retaining wall,the distance between the height of the first layer anchor and the bottom slab should be 1/3 height of the retaining wall and should not be more than 2.5 m in the distance from the bottom slab,and the height difference between each anchor rod layer is 2.5-3 m;(4) because the soil pressure on the anchor rod at the top of wall back is small,so the height of the top anchor rod should be set as the 1/3H to the wall top,and the suitable height should be 2-3 m;(5) the heights of double-layer anchor rod and anchored plate type building of the retaining wall should be 6-10 m,and the height of 3-layer anchor rod and anchored plate type building should be 10-12 m.