黄土地区单片地下连续墙水平承载特性试验研究

黄土地区某拱桥采用较为新颖的井筒式地下连续墙基础。为研究基础的水平承载特性,对单片地下连续墙进行了水平荷载试验。在墙身中布置钢筋计、测斜管,墙背布置土压力盒,采用慢速维持荷载法进行水平加载,试验时采集了墙顶、墙身位移、墙身应变、墙侧土抗力等现场数据,绘制了水平荷载H与力作用点处位移Y关系曲线。根据墙身实测应变采用标定断面法和理论计算法推算墙身弯矩,根据弹性地基梁理论由墙身弯矩推算墙侧土抗力,并与墙侧实测土抗力进行了对比分析。分析得出了单片墙水平承载力、不同深度处土抗力和水平位移关系图(q-y曲线),并推算了设计所需的土水平抗力系数的比例系数m值。试验和分析结果为黄土地区井筒式地下连续墙基础设计提供了重要依据。

Test on the lateral bearing behavior of a diaphragm wall in loess area

As a new type of foundation,the shaft diaphragm wall is employed for an arched bridge in loess area.To study the lateral bearing behavior,one single diaphragm wall is tested under lateral load.Strain gauges and deflection inclinometer are embedded inside the wall,and pressure cells are embedded at the back side of the wall.Slow sustaining load is applied in the test,the displacement,strain and soil resistance data are collected,and relationship between the lateral load,H,and the displacement,Y,is derived.The bending moment is calculated from the strain by using the calibrated section method and the theoretical method,soil resistance is calculated from the bending moment according to the elastic foundation beam theory,and comparisons with the actual values are conducted.The lateral bearing capacity,internal force and lateral displacement of the single diaphragm wall,the distribution of soil resistance,the relationship between soil resistance and lateral displacement at different depths(q-y curve) and the m-value of the lateral subgrade coefficient are calculated through analyzing the test data.