This paper will deeply analyze various reasons for foundation subsidence subsidence, including soil quality difference, groundwater change, improper construction, etc., and explain how these reasons interact with each other to eventually lead to safety problems of building structures. At the same time, a series of targeted preventive measures are provided, such as foundation reinforcement treatment, reasonable drainage design, construction quality control, etc., to help buildings effectively prevent foundation subsidence caused by uneven subsidence, and ensure building safety and stability.
I. Characteristics
foundation subsidence reinforcement caused by non-uniform settlement generally manifests as oblique cracks, horizontal cracks and vertical cracks. Oblique cracks generally occur at both ends of the lower longitudinal wall of the wall, most cracks through the two corners of the window, inclined to the direction of larger settlement, and develop from the bottom up, and gradually reduce upward; The crack width is large in the lower part and small in the upper part, and its number and width develop gradually with time. Horizontal cracks generally appear in pairs on the upper and lower corners of the wall between the Windows, the crack on the side with large settlement is below, and the crack on the side with small settlement is above. Vertical cracks are at the top of the center of the vertical wall and the bottom windowsill, and the cracks are wide at the top and narrow at the bottom.
Second, force analysis
1, oblique cracks are mainly due to the uneven subsidence of the foundation, so that the wall bears a large shear force, when the structural stiffness is poor, construction quality and material strength can not meet the requirements, resulting in wall cracking.
2, the horizontal crack of the window wall is due to the resistance of the upper part of the settlement unit, so that the window wall is subjected to a large horizontal shear force, and the horizontal crack occurs in the upper and lower positions.
3. The vertical cracks under the bottom windowsill are due to the anti-beam effect of the windowsill wall after the window wall bears the load, especially the large window or the window wall under the large concentrated load and the windowsill wall cracks due to excessive reverse deformation.
Iii. Reason analysis
1, the difference in soil quality of the foundation: the uneven soil layer of the foundation is one of the main reasons for the uneven settlement of the foundation. Geological factors include bedrock undulation, uneven local soil quality, large thickness of soft soil in lying layer, existence of hidden trenches and caves, and excessive water content in foundation.
2. Unreasonable investigation and design: If the investigation unit does not strictly follow the regulations during the investigation process, such as inaccurate hole placement or insufficient hole depth during the drilling process, it will lead to inaccurate geological reports and affect subsequent construction. In addition, unreasonable design, such as complex building shape, concave and convex corners, improper foundation treatment, will also lead to uneven foundation settlement.
3, improper construction: arbitrarily change the use of the building, increase the load, arbitrarily rebuild and expand the building, as well as the low mortar strength in the process of wall masonry, the ash joint is not full, will affect the stability of the foundation.
4, groundwater changes: the construction drainage scheme is unreasonable, a large number of underground water is mined around, etc., the change of the groundwater level will affect the gravity stress and compression modulus of the soil, and then affect the settlement of the foundation, resulting in uneven settlement of the foundation.
5. Foundation and foundation problem: the building transmits the load from the vertical system to the foundation through the foundation, and the reaction force generated by the foundation acts on the bottom surface of the foundation. Only when it is in balance with the axial force can the stability and integrity of the building structure be guaranteed. If some reasons cause shear, subsidence, soil slip and other dislocations of local foundation soil under the foundation, the balance between axial force and foundation reaction will be destroyed, and loose contact or no contact will occur between the foundation and foundation, the building will have uneven settlement, and additional stress will be generated inside the structure. As a result, the foundation subsidence reinforcement.
Iv. Preventive measures
1, foundation reinforcement treatment: according to the composition and characteristics of the weak foundation and the design requirements of the superstructure, the appropriate treatment method is selected to strengthen the weak foundation to achieve the purpose of improving the bearing capacity of the foundation and reducing the deformation and reducing the uneven settlement.
Hengxiang Hongye self-developed lossless controlled soil solidification technology, the use of new materials, 10-30mm microhole innovation process, light equipment, simple and fast operation method, can quickly strengthen the foundation of high-rise buildings and industrial plants, 1-90s consolidation soil, efficient completion of lifting and tilting. This technology does not need to be moved, does not affect the normal life of residents, especially for complex geology, poor construction environment, erratic construction or is not easy to dismantle changing building foundations. Flexible application in soft foundation (silt, silt soil, cohesive soil, etc.), lithologic geology (rock cracks, caves, rock mass, etc.), complex geological conditions (multi-layer strata, high groundwater level, uneven soil, etc.), effectively solve the problem of insufficient foundation bearing capacity, excessive foundation settlement, etc., is the best choice for settlement treatment measures.
2, construction quality control: in the construction process, should strictly implement the regulations, such as brick watering wetting degree, improve mortar workability, improve mortar fullness and so on. At the same time, pay attention to the reliable connection between masonry and non-structural components to improve the integrity of the wall.
3, reasonable drainage design: reasonable design of drainage pipes, reasonable management of groundwater, to avoid a large number of groundwater mining caused by foundation settlement.
4, load control: in the architectural design to minimize the self-weight stress, the use of light weight, high strength materials. At the same time, avoid arbitrarily changing the purpose of the building or increasing the load, so as not to increase the burden of the foundation.
5, settlement monitoring: the natural foundation and artificial foundation of the building settlement monitoring, timely discovery and treatment of foundation settlement problems.
In summary, the causes of foundation subsidence subsidence caused by uneven foundation subsidence are complex and diverse, which need to be prevented and treated from geological investigation, design, construction and use. The influence of uneven subsidence on the safety and stability of buildings can be effectively reduced by taking some preventive measures such as settlement reinforcement treatment of Hengxiang Hongye foundation.
foundation subsidence reinforcement https://en.hengxianghongye.com/Subsidence-Repair.html
