Measures to prevent foundation subsidence

1) In terms of architectural design

1. The building design strives for simplicity.

The height difference of the building facade should not be significantly different, and the difference in load acceptance should not be too large; Strive for simplicity in shape on a flat surface and try to keep it as simple as possible

Avoid concave and convex corners, and avoid excessive turning and bending on the plane, otherwise it will reduce its overall integrity and deformation ability. In addition, the aspect ratio of the building (the ratio of the length of the building on the plane to the height from the base) should be appropriately controlled. The smaller it is, the better the overall stiffness and the stronger the ability to adjust uneven settlement. Generally, it is controlled at around 2.5. For the stiffness of masonry, longitudinal and transverse walls should be arranged reasonably. Vertical and horizontal walls should be as continuous as possible, and the spacing between horizontal partition walls should not be too large, generally not exceeding 1.5 times the width of the building.

2. Set settlement joints.

Settlement joints divide the building into independent units, and the settlement of each unit does not affect each other. Generally, settlement joints should have sufficient width at the turning points of building plans, height differences (or load differences), appropriate locations for masonry load-bearing structures or reinforced concrete frame structures with excessive length to height ratios, locations with significant differences in soil compressibility, locations with different building structures or foundation types, and at the junctions of staged construction of buildings. The higher the building (the more floors), the wider the joints. The specific seam width and structure can be found in the specifications and relevant materials.

(2) In terms of structural design

1. Reduce the weight of the building.

Reducing the self weight of buildings can reduce the pressure on the foundation, which is an important way to prevent and alleviate uneven settlement. In practice, lightweight materials such as porous brick walls or other lightweight walls can be used; Choose lightweight structures such as prestressed reinforced concrete structures, light steel structures, and various lightweight spatial structures; Choose a foundation form with light weight and less soil cover, such as shallow buried wide foundation, foundation with semi basement or basement, or indoor elevated floor.

2. Set up ring beams and reinforced concrete structural columns.

Installing ring beams and structural columns in the walls of a building can enhance its overall integrity, improve its bending stiffness, and to some extent prevent or reduce the occurrence of cracks. Even if cracks appear, they can prevent their development.

(3) Construction aspect

1. When excavating the foundation pit, do not disturb the soil foundation. Usually, leave about 200mm of soil at the bottom of the pit, and manually excavate it when the cushion layer is constructed. If the soil at the bottom of the pit is disturbed, it should be excavated and backfilled with sand and gravel for compaction. Attention should be paid to the impact of pile driving, well point dewatering, and deep foundation excavation on nearby buildings.