以刚性基础上双级土工格栅加筋土挡墙为工程依托进行了现场原型试验研究,分析了施工期及竣工后1.5年期间各级挡墙加筋体底部竖向土压力、墙面板背部侧向土压力和土工格栅拉筋应变分布规律。试验结果表明:刚性基础上加筋体底部垂直土压力沿筋长方向由均匀等值分布变化到呈曲线型分布,最大值靠近墙面位置。柔性基础上加筋体底部垂直土压力沿筋长呈非线性分布,最大值靠近拉筋尾部。竣工后加筋体底部垂直土压力分布形式基本不变。施工期间加筋土挡墙墙背侧向土压力沿墙高呈曲线分布,且随上覆填土厚度的增加而增大,数值增长速率逐渐减小。墙背侧向土压力远小于主动土压力,竣工后其值随时间延续逐步减小。施工期各测试层位拉筋应变基本上随上覆填土厚度的增加而增大,应变沿筋长方向呈双峰值的非线性分布,各测试层位土:工格栅拉筋实测应变最大值均小于0.4%,竣工后拉筋应变基本无明显变化。试验结果可以为类似结构工程提供参考。
Monitoring of a two-step reinforced earth retaining wall on the rigid foundation is carried out by use of field tests. The monitoring includes the reinforced earth bottom vertical foundation pressure and lateral earth pressure of the reinforced soil wall facing and the tensile strain in the reinforcement during construction and 1.5a post-construction. The vertical foundation pressure under reinforced earth bottom is non-linear along the reinforcement length. The maximum value of the vertical pressure is near the facing for the rigid foundation of the lower wall, while the maximum value close to end of the reinforcement for flexible foundation of the upper wall. The measured lateral earth pressure within the reinforced soil wall is non-linear along the height and the value is less than the active lateral earth pressure. The distribution of tensile strain in the geogrid reinforcements within the wall is a double peak value and the maximum strain is less than 0.4%. These monitoring results can be used as a reference for future study and design of geogrid reinforced earth retaining wall systems.