基于砂土形成的SMW工法桩型钢 内力现场试验研究

SWM工法桩在我国软土地区应用广泛且研究较多，为推广其在砂土地区中的应用,在郑东新区郑州地铁1号线文苑北路站深基坑围护结构中采用了SMW工法桩。选取基坑中部3根具有代表性的工法桩为实测对象，通过在H型钢若干截面布置钢筋测力计，监测得到型钢的应力分布，并计算得出型钢的轴力和弯矩分布以及随施工过程的变化规律。研究表明：在基坑开挖过程中，型钢各个截面均为压应力，且基坑开挖深度越深，型钢下部所承受的轴力越大；随着基底位置下移，型钢所承受弯矩不断增大，反弯点逐渐下移，工法桩嵌固端也逐渐下移到基坑底部位置以下；与基坑开挖过程相比，在施筑内部结构和回填过程中，型钢轴力和弯矩均有所减小，但减小幅度有限。

Field Test Study on Internal Force of SMW Pile Steel Based on Sand Formation

SWM construction pile is widely used and studied in soft soil area of China. In order to promote its application in sandy soil area, SMW construction pile was adopted in deep foundation pit enclosure structure of Wenyuan north road station of Zhengzhou metro line 1 in Zhengdong new area. Three representative construction method piles in the middle of the foundation pit were selected as the measured objects. The stress distribution of the shaped steel was monitored by placing steel bar dynamometers in several sections of h-shaped steel, and the axial force and bending moment distribution of the shaped steel as well as the change rules along with the construction process were calculated. The results show that: in the process of foundation pit excavation, all sections of section steel are compressive stress, and the deeper the excavation depth of foundation pit, the greater the axial force under the section steel. As the position of the base moves down, the bending moment of the section steel increases, the anti-bending point gradually moves down, and the embedded end of the corresponding construction pile also gradually moves down below the base. Compared with the excavation of foundation pit, the axial force and bending moment of shaped steel are reduced in the process of construction and backfilling, but the reduction range is limited.