Design of backfill materials for driving steel sheet piles and pile forming tests in gravel layer

In order to solve the construction problem of inserting and driving steel sheet piles in pebble layer of rivers, a new type of lead-through backfill made of clay, bentonite, sawdust, cement and other materials is developed. Using the multi-factor orthogonal test method, the influence law and mechanism of the components of the new backfill materials on the compression, shear and impermeability properties of the backfill-solidified body are studied, and the construction mix proportion meeting the design requirements is given. The actual embedding effect of steel sheet piles is verified through the field comparative tests. The research results show that the content of silty clay has the most significant effect on the cohesion and compressive strength of the backfill aggregate, while the sawdust content has the most significant effect on the friction angle and impermeability of backfill aggregate. Under the maximum horizontal load, the average horizontal loading displacement, unloading displacement, compressive stress and proportional coefficient of horizontal reaction coefficient of foundation at the steel sheet pile top after using the new type lead hole backfill are 46%, 28%, 1.39%, and 2.8%, respectively, of the steel sheet pile after backfilling with on-site muck, which proves that the new type of backfill has greater soil stiffness and stronger resistance to deformation. The actual embedding effect of the piles is better. The new type of lead backfill has the comprehensive advantages of convenient material acquisition, convenient construction and good material performance, and can be popularized and applied in the construction of the same type of projects.