格栅加筋挡墙长期工作特性的现场试验研究

STUDY OF LONG-TERM PERFORMANCE OF REINFORCED EARTH RETAINING WALLS BY FIELD TEST

为了探讨山区高等级公路高强土工合成材料加筋陡坡路基长期工作特性,对某段分级直立式格栅加筋挡墙进行长期现场测试。测试结果表明:基底地基应力在初期沿格栅横向呈非线性分布,但随着时间的变化最终趋于直线分布;墙背和加筋体后侧向土压力沿墙高呈非线性分布,其值与基础支撑条件相关,且小于朗肯主动土压力,局部测点应力松弛;格栅拉力在加筋墙中部与阿斯曼能量法计算出的结果比较相近,但在顶部和底部相差甚远,同层格栅拉力沿格栅方向呈两端小中间大的梯形分布,格栅拉力随时间变化逐渐减小;加筋墙的潜在破裂面与规范规定的0.3H法相比,破裂面向加筋体内侧移动,随时间的变化不大;每级台阶墙的最大水平变形位置在墙中部,整个墙面最大水平变形位置在墙下部。

In order to discuss the long-term performance of reinforced earth retaining walls in high grade highway of mountainous area,the field test is conducted on the stepped geogrid reinforced soil retaining wall. It is found that the foundation vertical pressure of reinforced earth retaining wall is nonlinear along the reinforcement length at early stage;but as time progresses,the pressure eventually becomes a straight line stress distribution and the value gradually reduces. The testing lateral pressure of the panel is nonlinear along the height,and the value is less than the active lateral earth pressure,which is associated with the lateral displacement of the wall and reduces with the change in time. The tensile strain is similar to Assmann energy method in the middle of the wall,but it is far from the Assmann energy method at the top and bottom. The distribution of tensile strain along reinforcement is trapezoidal type with small value at both ends and large value at the middle,and the value of the tensile strain gradually reduces. The potential fracture plane is similar to 0.3H method in the upper;but at the lower wall,the potential fracture face moves to the reinforced retaining body and the change in displacement with time is little. The position of the maximum lateral displacement of each step is at the middle,and the maximum lateral displacement of the wall is at the lower wall.