天津市地处沿海地区,其软土地基特征极为明显,土壤天然含水率高,天然孔隙比大,压缩性高,抗剪强度低,渗透系数大。针对这些软土特点,回顾以往的护坡桩方案,多采用预制桩或灌注桩,由于基坑内外排水,造成土体含水量减少,土体萎缩,周围建筑物出现不均匀沉降,路面开裂,各种管道变位,引起较大的工程破坏。深基坑支护方案虽然种类较 Tianjin City is located in the coastal area, its soft soil features are very obvious, the soil has high natural moisture content, large natural void ratio, high compressibility, low shear strength, and large permeability coefficient. In view of the characteristics of these soft soils, reviewing the previous plans for slope protection piles, prefabricated piles or cast-in-place piles were mostly used. Due to the drainage inside and outside the foundation pit, soil moisture content decreased, soil shrinkage, uneven settlement of surrounding buildings, and cracking of pavements. The displacement of the pipeline caused great engineering damage. Although the type of deep foundation pit support program is relatively