For the foundation of the same structural unit, part of the natural foundation and part of the artificial foundation should not be adopted. It is also not advisable to adopt two or more types of soil layers with large differences in properties as the supporting layer. When the end approaches or partially enters the inclined top surface of the underlying soil layer, it is advisable to deepen the foundation or increase the pile length so that the bottom of the foundation of the pile ends are all in the same underlying house to avoid possible uneven settlement. The steel structure building site cannot avoid the marginal sections of rivers, lakes, and old rivers that may cause slippage or ground cracks during earthquakes, and targeted foundation stabilization measures should be taken and the foundation should be strengthened. If there is a liquefiable soil layer in the range of the foundation bearing layer under the foundation of a tall building in the earthquake area, measures should be taken to eliminate the adverse effects of the liquefaction of the soil layer on the superstructure.
1: Adopt the densification method to obtain the foundation, such as the Vibro-impact method, sand pile compaction method, dynamic compaction method, etc. When strengthening the foundation, it should be processed to the lower interface of the depth of soil liquefaction, and the standard penetration hammer of the treated soil layer The measured value of the number should be greater than the critical value of soil liquefaction.
2: When using a deep foundation, the depth of the bottom of the foundation buried in the stable soil layer below the liquid depth should not be less than 500mm.
3: When the multi-story steel structure factory building adopts the pile foundation, the length of the pile end projecting into the stable soil layer below the liquefaction depth shall be determined according to the bearing capacity of the pile, and shall not be less than the following values. Excavate the high-rise foundation bearing layer range All of the liquefiable soil layers.