Abstract: To solve the technical difficulties in a deep excavation support in the coastal soft soils such as new backfill soils and silty soils, the underreamed anchor by the jet grouting or ordinary prestressed anchor and cast-in-place pile are used in a project. The problems such as borehole collapse and insufficient anchoring force of the anchor construction in coastal soft soils are effectively solved by adopting such technologies as drilling with pipe, simultaneous installation of the anchor cable and full-length grouting, thus ensuring the safety and stability of the deep excavation supporting structure. On this basis, the acceptance test of the uplift capacity of the underreamed anchor by the jet grouting and ordinary anchor is performed. The acceptance test of the uplift capacity of anchor cable shows that the underreamed anchor by the jet grouting can provide enough uplift load in the coastal soft soils. Meanwhile, the result of the cable elongation value in the acceptance test less than the theoretical elongation value of the free section was discussed and analyzed, and improvement solutions were proposed. 

Key words: Deep Excavation, Underreamed Anchor by Get grouting, Coastal Soft Stratum, Acceptance Test, Stress and Deformation Characteristics