The residential buildings in this community have a total floor area of 148,900 square meters and have already rehoused 1,108 households comprising 3,378 people. This project is a 12-story residential building with a shear wall structural system and a raft foundation, with the raft slab 600 mm thick. A retaining wall is located on the south side of the building, and the main building structure is about 3 m from the retaining wall. The building is tilting toward the retaining wall. The settlement and tilt conditions of the building (as of July 30, 2023): the maximum southward tilt of the building is 117 mm, with a tilt rate of 4.0‰, exceeding the national code standard of 3‰. Calculations indicate that the maximum settlement difference in the north-south direction of the building is about 57 mm.

In August and September 2021, affected by heavy rainfall, a landslide occurred behind the community, producing new deformation and damage. Through deformation monitoring, as of October 17, 2021, the horizontal displacements at two monitoring points in the middle-rear part of the landslide were 2,592 mm and 2,420 mm respectively; at the front edge, the three monitoring points on the constructedanti-slide pileshad total displacements of 672.673 mm (west), 424.511 mm (center), and 232.778 mm (east) respectively, and no obvious tilting or pile fracture of the anti-slide piles was found; within the community site at the front edge of the landslide, the displacements at two displacement monitoring points were 251 mm and 104 mm respectively.

Manifestations of the settlement problem:

① Cracks appeared in some buildings within the community;

② The No. 1 retaining wall moved forward as a whole, with bulging deformation in the middle-lower part of the wall and local collapse, seriously threatening the safety of the above-mentioned buildings;

③ Cracks, bulging, and local anchor head detachment occurred in the anchor cable frame beams;

④ Roads within the community exhibited varying degrees of dislocation, warping, fracture, and other damage due to squeezing action.

(1) Multiple vertical slopes exist in the front edge area of the landslide, formingstress concentration phenomenaunder the thrust of the landslide, which greatly affects the building foundation and causes settlement and tilting of the building;

(2) The landslide area has abundant atmospheric precipitation. In seasons with sufficient rainfall, atmospheric precipitation infiltrates into the slope body and converts into groundwater. Becausesurface water seepage causes softening of the foundation soil, uneven settlement of the foundation occurs.

① Technical principle:By embedding anchor rods in the foundation to fix the pile-pressing frame and using the building's own weight as the reaction force, precast piles are pressed into the foundation in sections, and the pile bodies share the upper loads to improve the bearing capacity of the foundation.

② Limitations:

· Pile-pressing holes must be cut in the foundation, which may cause local damage to the original structure

· High requirements for construction space; not suitable for narrow sites

· Limited reinforcement effect on deep soft soil layers

① Technical principle:The soft soil layer at a certain depth below the foundation base is excavated and replaced with materials of higher strength such as sand, gravel, and plain soil, which are compacted in layers to form a cushion, thereby improving the bearing capacity of the foundation and spreading the upper loads.

② Limitations:

· Requires extensive excavation and replacement materials, with a large workload and a long construction period

· Only applicable to shallow soft soil layers (treatment depth usually ≤3 m)

· Poor applicability to sites with deep soft foundations or high groundwater levels

Traditional reinforcement and rectification is often accompanied by high-cost pain points such as relocation and resettlement and construction disturbance to residents. Today, the "non-disturbance rectification" solution, led bynon-destructive controllable soil solidification technology, is redefining the safety governance standards for building foundation settlement.

Non-destructive controllable soil solidification technologyusesnew special composite materialsinjected into the foundation throughmicro-hole technology. The composite materials can penetrate and fill the voids in the soil body and rapidly consolidate with the soil, enhancing the density and stiffness of the soil body and forming a high-strength composite foundation. As the soil pressure increases and density rises, an upward jacking force is formed, lifting the residential building and thereby correcting the tilt.

The total height of the building is 32.8 m. On the premise of ensuring the safety and stability of the upper structure of the building, lifting was carried out sequentially and cyclically from the locations with larger settlement values to those with smaller settlement values. During the lifting process, automated monitoring instruments were deployed for real-time monitoring. It took 30 days to finally complete the lifting and rectification of the building tilt, bringing themaximum tilt rate under control within the national standard of 3.0‰and achieving settlement stability.

In this project, the client highly recognized our company's technical strength based on the actual reinforcement and rectification results,commenting"Hengxiang Hongye's new technology saved 50% of the time compared with traditional rectification methods; the entire construction process involved no excavation and no noise, with zero disturbance to the living environment, and the construction cost for this building was reduced by 60%. It is both cost-saving and efficient, requires no moving of furniture, and is safe and environmentally friendly. It is a truly reliable technology that benefits the people!"