Introduction to foundation foundation reinforcement, foundation foundation reinforcement?

Foundation reinforcement, that is, because the natural foundation is weak and can not meet the requirements of foundation strength, deformation, etc., then it is necessary to treat the foundation in advance, and improve the engineering characteristics of the foundation soil by means of replacement, tamping, compaction, compaction, drainage, cementation, reinforcement and thermal, so as to achieve the purpose of foundation reinforcement.

The purpose and significance of foundation treatment are mainly as follows:

1.Improve the shear strength of foundation soil.

The shear failure of the foundation is manifested in: the bearing capacity of the foundation of the building is insufficient; The structure is unstable due to eccentric load and lateral earth pressure. Uplift of adjacent foundations due to fill or building loads; slope instability during earthwork excavation; When the foundation pit is excavated, the bottom of the pit is raised. The shear failure of the foundation is reflected in the insufficient shear strength of the foundation soil, therefore, in order to prevent the shear failure, certain measures need to be taken to increase the shear strength of the foundation soil.

2.Reduces the compressibility of the foundation soil.

The compressibility of foundation soil is manifested in the settlement and differential settlement of buildings. Due to the load of filling or building, the foundation produces consolidation and settlement; The negative friction force acting on the foundation of the building causes the settlement of the building; settlement and uneven settlement of a wide range of foundations; Foundation pit excavation causes subsidence of adjacent ground; Consolidation and settlement of the foundation due to precipitation. The compressibility of the foundation is reflected in the magnitude of the compressive modulus index of the foundation soil. Therefore, measures need to be taken to improve the compressive modulus of foundation soil, so as to reduce the settlement or uneven settlement of the foundation.

3.Improve the permeability characteristics of foundation soil.

The permeability of foundation soil is manifested in the foundation leakage caused by foundations such as embankments; In the foundation pit excavation project, quicksand and pipe gushing are generated due to the thin layer of silt or silt in the soil layer. All of the above are the problems that arise in the movement of groundwater. To this end, measures must be taken to reduce the permeability of the foundation soil or to reduce its water pressure.

4.Improve the dynamic characteristics of foundation soils.

The dynamic characteristics of the foundation soil are manifested in the fact that when saturated loose silt fine sand (including part of the silt) will be liquefied; Due to traffic loads or piling, etc., the adjacent foundations vibrate and sink. To this end, measures need to be taken to prevent the liquefaction of the foundation and to improve its vibration characteristics to improve the seismic performance of the foundation.

5.Improve the poor foundation characteristics of special soils.

It is mainly to eliminate or reduce the collapsibility of loess and the expansion and contraction of expansive soil.

The foundation treatment generally includes: 1, soil replacement cushion method 2, vibration density, compacting method 3, drainage consolidation method 4, replacement method 5, reinforcement method.

6. Cementation method 7. Cold and heat treatment method, 7 methods.

Construction method. There are mainly anchor static pressure prefabricated pile reinforcement technology; high-pressure jet grouting pile reinforcement technology; chemical grouting reinforcement technology; Composite foundation reinforcement technology of deep mixing pile; Pillar-clad new and old foundation connection technology; Reinforcement planting type new and old foundation edge joint technology, etc.

1. Grouting reinforcement method.

The grouting reinforcement method is suitable for foundation reinforcement such as sand, silt, cohesive soil and artificial fill. It is generally used to prevent seepage and plug leakage, improve the strength and deformation modulus of foundation soil, and control formation settlement.

Construction technology of pressure grouting:

Pressure grouting construction process: drilling, pigging, pipe playing, grouting, pipe extubation, pigging.

a. Drilling: The electric drilling machine drills holes at the layout position and drills to the design elevation;

b. Pigging: water injection to clean the hose and seamless steel pipe, check whether the grouting can be guaranteed;

c. Pipe: Insert the seamless steel pipe into the design elevation position according to the design requirements in stages;

d. Grouting: The mortar mixer mixes the cement slurry, sucks it into the grouting pump, and injects the seamless steel pipe through the hose.

2.Root stump method.

The root pile method is suitable for the repair and addition of existing buildings on the foundation soil such as silt, silty soil, cohesive soil, silt, sand, gravel soil and artificial fill, the renovation of ancient buildings, and the crossing of underground railways.

Selection of drilling machinery and equipment: Drilling equipment is reasonably selected according to the type of foundation, geological conditions and site conditions, and the soft clay can be protected by clear water, and mud must be used for silt and sand.

3.Anchor static pile method.

The anchor static pile method is suitable for foundation soil such as silt, silty soil, cohesive soil, silt and artificial fill.

Standard Atlas of Anchor Static Piles in Shanghai: Reinforced Concrete Anchor Static Piles (Shanghai) 2009 Shanghai G504

4.Increase the base area method.

For the foundation that the bearing capacity of the foundation is not much different after review, the method of increasing the bottom surface area of the foundation can be used to improve the contact area between the foundation and the foundation, so as to reduce the soil stress and achieve the purpose of reinforcing the foundation.

When it comes to foundation reinforcement, relevant construction people are still relatively unfamiliar, what are the common problems of general foundations? What are the main reasons? The following is the basic content of the relevant foundation reinforcement for construction professionals, which is as follows:

Reinforced foundation refers to the foundation that is reinforced by soil replacement, tamping, organic or inorganic binder stabilization, etc.

The common problems of foundation reinforcement mainly include: (1) wall cracking (2) foundation fracture or arch (3) excessive sinking of the building (4) foundation sliding (5) foundation liquefaction failure and other problems, what are the main reasons for these problems:

1) Do not investigate carefully, there is no complete survey data. The geological survey report is the basic basis for the design of the foundation of the building. Design based on experience without survey, or the survey work is not serious and meticulous, the survey report fails to accurately reflect the actual geological conditions, and even misses the detection of local interlayer weak soil, does not detect local soil pits, Gujingsen Zheng draft, or provides inaccurate soil quality indicators, which will lead to design errors, resulting in foundation accidents.

2) The design scheme is not thoughtful. The selection and determination of the foundation design scheme is very important, and it must be adapted to local conditions, safe and reliable, and economically reasonable. The geological conditions of some buildings are poor and the changes are complex, so it is more necessary to choose the design scheme reasonably and do a good job in calculation and analysis, otherwise it will cause cracking or tilting of the building structure and endanger safety.

3) Poor construction quality. Foundation clusters and foundations are generally concealed projects, and common problems in construction include: poor construction management, failure to follow design drawings and procedures; construction without survey; Cutting corners, the strength of masonry and concrete cannot meet the design requirements, and some even fill bricks in the concrete; After excavation, the foundation is poured without checking the groove, or after excavation, it is found that there is an accident and does not deal with it carefully.

In view of these problems, the commonly used foundation reinforcement methods include: (1) grouting reinforcement method, (2) root pile method, (3) anchor static pile method, (4) increasing the foundation bottom area method, and (5) high-pressure jet grouting method.

(1) Mechanical compaction method: by improving its compactness, its strength is improved and its compressibility is reduced.

2) Strong compaction method: during construction, the vibration is large and the noise is large, which has an impact on the safety of nearby buildings and the normal life of residents.

3) Soil replacement cushion method: it is to dig out the natural weak soil layer, layer backfill strength is high, low compressibility and non-corrosive sand, plain soil, ash, industrial waste and other materials, compacted or compacted as the foundation cushion.

4) Drainage consolidation method: It is suitable for foundation treatment of saturated clay such as silt, silty soil, and flush fill soil.

5) Compacting method: mainly suitable for the treatment of soft sand soil, plain fill soil, miscellaneous fill soil, collapsible loess, etc.

6) Chemical reinforcement method: refers to the treatment method of using chemical slurry to pour or spray into the soil to consolidate the soil to strengthen the foundation.

Foundation reinforcement refers to the reinforcement measures for the foundation of engineering buildings to ensure the stability and safety of the building. Generally speaking, the reason for foundation reinforcement is that there are problems with the foundation on which the building is located, such as soft soil, irregular foundation shape, large load, water level change, etc.

There are usually several methods of foundation reinforcement:

1.Use surface fill or reinforcing materials to change the properties of the foundation to strengthen and improve, such as filling stones, sand, gravel, etc.

2.Set up underground reinforcement structures to firmly connect the foundation and the building, such as setting up cantilevered walls, ground anchors, reinforced concrete retaining walls, etc.

3.Grouting or grouting reinforcement of the foundation. Grouting is the drilling of holes between the foundations or at the bottom of the foundation, injecting high-strength cement slurry or other specific materials into them to fill the voids to increase the density and strength of the foundation.

The grouting process is similar to grouting, but the properties of the injected materials are slightly different, making it suitable for regulating the water table.

4.To carry out deep reinforcement, such as steel sheet piles, cement mixing piles, concrete piles, etc., these methods need to be carried out by excavation machinery and construction tools, and the pile body is driven into the deep part to solidify the foundation.

Foundation reinforcement needs to choose different reinforcement methods according to the specific situation and different building structures to ensure the safety and stability of the building.

Foundation reinforcement refers to the reinforcement of the existing or to be built building foundation by applying different technical means, that is, soil replacement treatment, manual or mechanical tamping (compaction), vibration compaction, soil (ash), sand, stone pile compacting and bending Xianghe reinforcement, etc. I looked at ** before and found that there is a foundation reinforcement company called Hengxiang Hongye in Yanwang in China, which has developed a soil solidification foundation reinforcement technology. I've never seen this method before, and I don't know if it's reliable.

Anyway, it looks quite advanced, and I just don't know how to write a professional course. I'm going to take a closer look at it and be comfortable if it's suitable.

Foundation reinforcement refers to the fact that the natural foundation is very weak and cannot meet the design requirements of the foundation bearing capacity and deformation, and the foundation needs to be manually treated before the foundation can be built, which is the reinforcement of the foundation. Foundation reinforcement is in accordance with the requirements of the superstructure for the foundation, the necessary reinforcement of the foundation, improve the bearing section of the foundation soil, ensure the stability of the foundation, reduce the settlement of the superstructure or uneven holding and burial settlement, eliminate the collapsibility of collapsible loess and improve the liquefaction resistance method.

Ground reinforcement or treatment can be divided into the following four categories according to its different principles and practices.

1) Drainage consolidation method. Various methods are used to make the soft clay foundation drain and consolidate, and the strength of the soil and the compressibility of the soil are reduced from the leakage.

2) Vibrating and squeezing method. Adopt certain measures, such as vibration, compacting, etc., to densify the foundation soil, so as to improve the strength of the soil and reduce the compressibility of the soil.

3) Replacement and mixing method. Replace part of the soft soil in the soft soil foundation with sand, gravel and other materials, or mix cemented hardening materials in the soft foundation, or inject chemical liquid into the foundation to produce cementation to form solidification, so as to improve the bearing capacity of the foundation and reduce the compression.

4) Reinforcement method. By burying a strong geopolymer in the foundation, the purpose of reinforcing the foundation is achieved.

When choosing the ground early or foundation treatment scheme, it should be based on the actual situation of the project and the foundation, and taking into account the conditions such as the construction speed and the equipment required for reinforcement, and make a comprehensive comparison of various reinforcement schemes, so as to be economically reasonable and technically reliable.