地基土处理（Foundation soil treatment）.docVIP

地基土处理（Foundation soil treatment） Method and construction technology of bad foundation soil, treatment and reinforcement Substitution method (1) replacement method It is to dig out the bad foundation soil of the surface layer, and then backfill the soil with better compaction characteristics to compaction or tamping, and form a good bearing stratum. Thereby, the bearing capacity characteristics of the foundation can be changed, and the deformation resistance and stability can be improved. Construction points: the soil layer to be converted, pay attention to the stability of the pit; to ensure the quality of the filling; filling should be layered and compacted. (2) vibro replacement method By using special vibratory machines and tools, under the high pressure water jet, the edge of the edge is washed and made into holes in the ground, and then piles of gravel or gravel are formed in batches to form a pile body. The composite foundation is made up of the pile body and the base soil in order to improve the bearing capacity of the foundation and reduce the compressibility. Note: the construction of gravel pile bearing capacity and settlement largely depends on the in-situ soil lateral constraints on it, the constraint effect is weaker, the effect of gravel pile is worse, so the method for soft clay strength is very low when must be careful. (3) tamping (extrusion) replacement method The pipe (hammer) is put into the soil by means of an immersed tube or a rammer, so that the soil is pushed to the side, and the gravel or sand is filled in the pipe (or tamping hole). The pile and soil in composite foundation, the soil compaction due to extrusion, lateral extrusion, surface uplift, soil pore water pressure increases, when the dissipation of excess pore water pressure after the soil strength is also a corresponding increase. Construction note: when the filling is good permeability of sand and gravel, it is a good vertical drainage channel. Two, preloading method (1) surcharge