Engineering method for settlement reinforcement and lifting of residential building foundation

Abstract

Disclosed in the present invention is an engineering method for settlement reinforcement and lifting of a residential building foundation, comprising stratum structure exploration, curtain reinforceme

Description

An engineering method for reinforcing and lifting the foundation settlement of residential buildings. Technical Field This invention relates to a foundation reinforcement and lifting project for residential buildings, specifically a method for reinforcing and lifting settlement-affected residential building foundations, belonging to the field of building foundation processing and lifting technology. Background Technology In building construction, raft foundations are widely used due to their high bearing capacity, adaptability to soil layers with weak bearing capacity, and good overall integrity. With the construction of high-rise or super high-rise buildings, the requirements for the geological conditions of the site are also becoming increasingly stringent. The foundation soil mainly consists of silty clay and silt, belonging to medium to high compressibility soil layers. Uneven foundations, low bearing capacity, and poor soil properties are significant causes of uneven settlement. Furthermore, for units located on the Yellow Sea alluvial plain, the high groundwater level and long-term groundwater erosion weaken the soil layers, also contributing to uneven settlement. Pouring large areas of foundation soil near buildings causes significant settlement of the soil around the piles under load, generating negative skin friction on the piles. Additionally, the lateral deformation of the soil around the piles compresses adjacent piles, leading to horizontal displacement and flexural deformation. When the pile top is under load, the load interacts with the negative skin friction and lateral compressive force, affecting the pile's performance and potentially causing significant secondary bending moments and shear forces, leading to pile fracture. Summary of the Invention The purpose of this invention is to provide an engineering method for reinforcing and raising the foundation of residential buildings to solve the problem. This invention achieves the above objective through the following technical solution: an engineering method for reinforcing and lifting the foundation settlement of a residential building, comprising the following steps. Step 1: Stratigraphic exploration. Based on differences in soil type, color, state, and inclusions, the strata within the exploration depth range are divided into 9 layers. The characteristics and distribution of each soil layer are as follows: The first layer is a slightly dense silt layer, the second layer is a slightly dense silty clay layer, and the third layer is medium density silt. The first layer is dense silt, the second layer is silt interbedded with silty clay, the third layer is silt, the fourth layer is plastic silty clay, the fifth layer is fine sand, the sixth layer is plastic-stiff silty clay, and the ninth layer is fine sand. Step 2: Curtain reinforcement. Curtain grouting reinforcement is carried out around the building. The skip-hole method is used to reinforce the structure in layers by retreating. After each reinforcement section, the drill rod is pulled up 0.5 to 1.0m and the reinforcement continues, circulating upwards to the foundation slab; a curtain wall is formed around the building foundation. Step 3: Shallow reinforcement and strengthening. The silty clay layer under the foundation slab is reinforced and strengthened to improve the density and rigidity of the foundation soil. The purpose is to act as a buffer zone during the lifting operation, so that the lifting force is more even. Step 4: Deep reinforcement. Continue drilling down to the 5th layer of silt and begin the retreating layered reinforcement treatment of the soil around the original pile to increase the soil friction around the pile and form an integral stone body. Step 5: Stabilizing and Lifting the Intermediate Layer. After the upper and lower layers of solidification are completed, the intermediate base layer on the settlement side is stabilized and lifted. The grouting pressure and grout mix ratio are adjusted appropriately on the settlement side. The grout continuously fills and compacts the foundation soil layer. As the density of the foundation soil layer increases and the pressure rises, a lifting force is generated, thereby achieving the building lifting effect. This not only improves the bearing capacity of the foundation but also achieves the purpose of lifting and correcting the building's deviation (the amount of lifting and correction should be determined based on the actual site conditions and the safety of the building structure). After the foundation reinforcement and lifting are completed, an integral raft composite foundation is formed. Step Six: Construct composite foundation reinforcement supports. After the building reinforcement and lifting meet the requirements, construct multiple composite foundation reinforcement supports at the bottom of the raft-type composite foundation. The reinforcement depth extends to approximately 3 meters below the pile bottom to improve the bearing capacity of the pile end bearing layer and enable the building foundation to meet the settlement stability requirements. As a further aspect of the present invention: in step one, the holes for curtain reinforcement are arranged on the outside of the building foundation slab, with a hole spacing of about 2.5m, a hole depth of 12.0m below the foundation slab, and the curtain reinforcement range extends 3.0m beyond the building foundation. As a further aspect of the present invention: in steps two and three, the reinforcement holes are all indoor holes, arranged in a quincunx pattern, drilled vertically, with the shallow reinforcement drilling depth as the basis. The drilling depth for deep reinforcement is 4.0m below the foundation bottom, and the drilling depth for deep reinforcement is 7.0m to 12m below the foundation bottom. Both shallow reinforcement and deep reinforcement cover the entire area of ​​the foundation slab. As a further aspect of the present invention: in step five, the lifting holes are arranged by using some of the reinforcement holes as lifting holes on the side of the building settlement, and the hole depth is 4.0m to 7.0m below the foundation plate. The beneficial effects of this invention are: 1. Shallow reinforcement employs a progressive, layered reinforcement process to stabilize the foundation and reduce the settlement rate. The purpose of shallow reinforcement is to act as a buffer zone during lifting operations, resulting in more even stress distribution during lifting. 2. Deep filling reinforcement adopts a backward layered reinforcement treatment. After each section is reinforced, the drill rod is pulled up 0.3m to 0.5m and grouting is continued. Through layer-by-layer reinforcement, the foundation soil layer achieves a uniform and dense structure. 3. After the building is raised to the required height, the foundation below the foundation slab is reinforced with grout to form an integral raft-type composite foundation reinforcement, thereby enabling the building foundation to meet the requirements for settlement stability and to correct deviation. 4. Construct a composite foundation support system, similar to pile foundations, at the four corners of the building and below the main load-bearing walls inside. This system is formed by repeated back-and-forth grouting to support the upper load. After the building foundation is reinforced, the foundation achieves the required settlement stability and corrects any deviations. Attached Figure Description Figure 1 is a schematic diagram of the building lifting principle of the present invention; Figure 2 is a schematic diagram of the hole arrangement in Building 15# according to Embodiment 2 of the present invention; Figure 3 is a cross-sectional schematic diagram of the reinforcement range of Building 15# in Embodiment 2 of the present invention; Figure 4 is a schematic diagram of the hole arrangement in Building 16# according to Embodiment 3 of the present invention; Figure 5 is a cross-sectional schematic diagram of the reinforcement range of Building 16# in Embodiment 3 of the present invention; Figure 6 is a schematic diagram of the hole arrangement in Building 17# according to Embodiment 4 of the present invention; Figure 7 is a cross-sectional schematic diagram of the reinforcement area of ​​Building 17# in Embodiment 4 of the present invention. Detailed Implementation The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Example 1 Please refer to Figure 1. An engineering method for reinforcing and lifting the foundation settlement of a residential building includes the following steps: Step 1: Stratigraphic exploration. Based on differences in soil type, color, state, and inclusions, the strata within the exploration depth range are divided into 9 layers. The characteristics and distribution of each soil layer are as follows: The first layer is a slightly dense silt layer, the second layer is a slightly dense silty clay layer, the third layer is a medium dense silt layer, the fourth layer is a silt interbedded with silty clay layer, the fifth layer is a silt layer, the sixth layer is a plastic silty clay layer, the seventh layer is a fine sand layer, the eighth layer is a plastic to stiff plastic silty clay layer, and the ninth layer is a fine sand layer. Step 2: Curtain reinforcement. Curtain grouting reinforcement is carried out around the building. The skip-hole method is used for layered reinforcement. After each reinforcement section, the drill rod is pulled up 0.5 to 1.0m and the reinforcement continues, circulating upwards to the bottom of the foundation; a curtain wall is formed around the building foundation. Step 3: Shallow reinforcement and strengthening. The silty clay layer under the raft foundation is reinforced and strengthened to improve the density and rigidity of the foundation soil. The purpose is to act as a buffer zone during the lifting operation, so that the lifting force is more even. Step 4: Deep reinforcement. Continue drilling down to the 5th layer of silt and begin the retreating layered reinforcement treatment of the soil around the original pile to increase the soil friction resistance around the pile and form an integral stone body. Step 5: Stabilizing and Lifting the Intermediate Layer. After the upper and lower solidification layers are completed, stabilize and lift the intermediate base layer on the settlement side. Adjust the grouting pressure and grout mix ratio appropriately on the settlement side. Continuously fill and compact the foundation soil layer with grout. As the density and pressure increase, the foundation soil layer... This creates a lifting force, thereby achieving the building lifting effect, which improves the bearing capacity of the foundation and also achieves the purpose of lifting and correcting the building's deviation (the amount of lifting and correction should be determined based on the actual site conditions and the safety of the building structure); after the foundation reinforcement and lifting are completed, an integral raft composite foundation is formed; Step Six: Composite Foundation Reinforcement Support. After the building reinforcement and lifting meet the requirements, multiple composite foundation reinforcement supports are constructed at the bottom of the raft-type composite foundation. The reinforcement depth extends to approximately 3 meters below the pile bottom to improve the bearing capacity of the pile end bearing layer and enable the building foundation to meet the settlement stability requirements. In this embodiment of the invention, step one, specifically including the characteristics and distribution of each soil layer, includes: Slightly dense silt layer: Yellowish-brown, moist, slightly dense, rapid shaking reaction, uniform soil texture, no luster reaction, low dry strength, low toughness, locally manifested as a loose silty thin layer, the surface layer is cultivated soil containing a small amount of plant roots, and the soil layer locally contains plastic silty clay. Slightly dense silty clay layer: Yellowish-brown, moist, slightly dense, moderate shaking reaction, uniform soil texture, no luster reaction, low dry strength, low toughness, contains iron spots, mica flakes and a small amount of ginger stone, locally high clay content, interspersed with thin layers or lenses of soft plastic to plastic silty clay. Medium-dense silt layer: Yellowish-brown, moist, medium-dense, low dry strength, rapid shaking reaction, dull appearance, low toughness. Locally contains thin layers of silt with a high sand content; the main components are quartz and feldspar. This layer is discontinuous and locally pinches out. Silt interbedded with silty clay layers: Yellowish-brown to brownish-gray, moist, slightly dense, moderate shaking reaction, no gloss reaction, low dry strength, low toughness, interlayered with thin layers or lenses of soft to plastic silty clay. Silty layer: Yellowish-brown, moist, slightly dense, low dry strength, moderate shaking reaction, no luster, low toughness. Locally mixed with a thin layer of powdery residue, containing a small amount of mica flakes and iron oxides; Plastic silty clay layer: Grayish-brown, primarily plastic, with medium dry strength, no shaking reaction, moderate toughness, slightly glossy, containing small amounts of iron oxides, small ginger stones, calcareous nodules, snail debris, etc. Locally, it contains a medium-dense silty hard layer; Fine sand layer: Yellowish-brown, saturated, dense, with a general particle size distribution. Its main mineral components are quartz and feldspar, containing iron and manganese, mica flakes, and occasionally snail fragments and small gingerstone. Plastic-hard plastic silty clay layer: Brownish-yellow, plastic to stiff plastic, medium dry strength, no shaking reaction, medium toughness, slightly glossy, contains a small amount of calcareous nodules, snail debris, etc., and locally contains a thin layer of medium-dense silt. In this embodiment of the invention, in step one, the holes for curtain reinforcement are arranged on the outside of the building foundation slab, with a hole spacing of about 2.5m, a hole depth of 12.0m below the foundation slab, and the curtain reinforcement range extends 3.0m outward from the building foundation. In this embodiment of the invention, in steps two and three, the reinforcement holes are all indoor holes arranged in a quincunx pattern, drilled vertically, with the shallow reinforcement drilling depth 4.0m below the foundation bottom and the deep reinforcement drilling depth 7.0m to 12mm below the foundation bottom, and the scope of both shallow reinforcement and deep reinforcement is the full area reinforcement of the raft foundation. In this embodiment of the invention, in step five, the lifting holes are arranged using some of the reinforcement holes as lifting holes on the side of the building settlement, and the hole depth is 4.0m to 7.0m below the foundation plate. In this embodiment of the invention, in step five, a high-alumina iron composite grout is selected for grouting construction, and the grout fills the voids in the foundation soil layer and solidifies to form a new structure. The grouting fluid formulation can be as follows: Grout A consists of the following raw materials in parts by weight: 70-90 parts of metal oxides and / or metal hydroxides, 0.5-1.2 parts of composite retarder, 0.5-0.7 parts of water-reducing agent, 0.7-1.5 parts of acid-base buffer, 3-5 parts of composite stabilizer, and 0.5-1.5 parts of composite surfactant. The metal oxides can be any combination of two of magnesium oxide, aluminum oxide, or magnesium phosphate; the composite retarder is urea and sodium tripolyphosphate; the water-reducing agent is a polycarboxylate superplasticizer; and the acid-base buffer is magnesium carbonate or hydroxide. Potassium; the composite stabilizer is at least two of hydroxymethyl cellulose, n-alkyl cetyl alcohol, starch ether, and cellulose ether; the composite surfactant is at least two of alkyl polyoxyethylene ether, benzylphenol polyoxyethylene ether, and alkyl sulfonate. When two or more different materials are used in each of the above individual components, they can be prepared in equal quantities. The use of two materials is mainly to prevent the failure of one of them, so as to make the overall composite grout effect more stable. Grout B is composed of the following raw materials in parts by weight: 30-40 parts of phosphate and 0.2-1 parts of defoamer. Among them, the phosphate can be diammonium hydrogen phosphate or potassium dihydrogen phosphate; the defoamer can be an organosilicon defoamer or a polyether defoamer. Grout A and grout B are mixed with water at a weight ratio of 100:40-50 to form grouts, which are then injected into the grouting pipe through different pipelines, where they converge and react at the grout outlet and solidify in the soil. The difference in the initial setting time of the composite grout is mainly achieved by adjusting the specific gravity of the composite retarder. Preferably, during the pressure grouting process, less water should be added to increase the grout concentration, so as to better compress the surrounding soil (e.g., grout A and grout B are mixed with water at a weight ratio of 100:40); during other grouting processes, more water should be added and the grout concentration should be lower (e.g., grout A and grout B are mixed with water at a weight ratio of 100:50).

[0096] In this embodiment of the invention, in step six, the composite foundation support body extends to the four corners of the building and under the main load-bearing walls. In this embodiment of the invention, during grouting, the reinforcement grouting pressure is 0.3~ 1.2MPa, with an increase in grouting pressure of 0.5~2.5Mpa. In this embodiment of the invention, the grouting process specifically includes... Hole positioning According to the drawings, make positioning marks based on the actual site conditions. Adjust the drilling direction (vertical or inclined) according to the specific site conditions; at the designated drilling points, construction personnel must strictly follow the requirements for drilling. Drilling rig in place After the drilling rig is in place, it should be leveled and centered. The angle of the drill rod should be adjusted and aligned with the hole position. The drilling rig must not be moved. Before drilling, the equipment should be run dry to ensure normal operation of the drilling rig. Drilling The drilling and grouting machine was used for hole formation, with a drilling diameter of 42mm. Before drilling, the concrete protective layer was removed, and the hole was drilled between adjacent reinforcing bars. Based on the actual site conditions, the construction personnel constantly monitored the changes in the drilling during the drilling process to ensure smooth progress. Records were kept during drilling to provide reference data for the grouting operation. Prepare slurry To control the grout setting time and diffusion radius and achieve good grouting and sealing effects, engineering experience shows that the grout setting time can be accurately controlled within a few seconds to tens of minutes. The setting time requires a reasonable mix ratio to achieve the ideal state. Strictly follow the mixing ratio when adding materials. Do not put rope ends, paper scraps, or other debris into the mixer during mixing. The mixed slurry must be filtered through a sieve before entering the grouting machine. The mixing time should not be less than 3 minutes to avoid uneven mixing of the slurry. Grouting operation As required, the grouting pressure of each hole must be strictly controlled. The grout flow rate should also be closely monitored during grouting. Grouting should be stopped immediately if the pressure suddenly rises or falls, or if grout overflows. The cause of the abnormality must be identified, and necessary measures must be taken before grouting can continue. Grouting must be continuous. If it is interrupted for any reason, the cause of the interruption should be identified, and corrective measures should be taken as soon as possible to resume grouting. Grouting should be carried out in sequence. If cross-grouting occurs, the cross-grouting holes should be grouted simultaneously. Dust control for grouting materials is achieved by enclosing the site with barriers; grout diffusion control is achieved by adjusting the grout mix ratio to control the grout's penetration capacity and setting speed; grouting pressure control is achieved by constantly observing the dynamics of the ground surface, the readings on the grouting pressure gauge, and the skilled operation of the grouting machine. Sealing holes After grouting is completed, the opening is sealed and smoothed with cement mortar of the same or higher grade as the ground surface. In this embodiment of the invention, in step five, the lifting operation is carried out in an intermittent, cyclical manner, with a daily lifting height of less than 10 mm. Example 2 Please refer to Figures 2-3, which illustrate an engineering method for reinforcing and raising the foundation of a residential building to address settlement, using the reinforcement and raising scheme for residential building #15 as an example: I. Hole Position Layout Curtain reinforcement hole arrangement and depth: The holes are arranged outside the building foundation slab, with a spacing of about 2.5m between holes and a depth of 12.0m below the foundation slab (the actual hole positions and depths will be adjusted according to the actual site conditions). Reinforcement Hole Layout and Depth: Holes will be laid out indoors, with a tentative spacing of 3.3m, in a staggered pattern. Drilling will be vertical. For shallow reinforcement, the drilling depth will be approximately 4.0m below the foundation bottom. For deep reinforcement, the drilling depth will be 12m below the foundation bottom (reaching the 5th layer of silt). Hole positions and depths should be adjusted based on actual site conditions, avoiding shear walls and CFG piles. The maximum hole spacing should not exceed 4.0m. (See the hole layout diagram for details.) Lifting hole arrangement: On the side of building settlement, some reinforcement holes will be used as lifting holes, with a hole depth of 4.0m to 7.0m below the foundation slab; if necessary, inclined holes will be drilled on the outside of the foundation slab or outdoors as lifting holes, with a drilling depth of approximately 4.0m to 7.0m below the foundation slab. (The location of outdoor and indoor lifting holes should be adjusted according to the actual site conditions). II. Scope of Reinforcement Curtain reinforcement scope: The curtain reinforcement scope extends 3.0m outward from the building foundation, and the reinforcement depth is 12.0m below the foundation slab. The volume of the reinforced body is approximately 6188m3 (total curtain length 171.9m, width 3.0m, height 12.0m). Shallow reinforcement scope: The reinforcement scope is the full area of ​​the raft foundation, with a planar area of ​​approximately 808.0 m2. The reinforcement depth is approximately 4.0 m below the foundation bottom. The reinforcement scope will be adjusted according to the on-site drilling conditions. Scope of deep reinforcement: The scope of planar reinforcement is the full area of ​​the raft foundation, with a planar area of ​​approximately 808.0 m2 and a reinforcement depth of 7.0 m to 12.0 m below the bottom of the raft foundation; The stable uplift range of the intermediate layer: The stable uplift layer is about 3.0m between the shallow reinforcement and the deep karst cave filling reinforcement layer. After the foundation lifting, correction, and reinforcement were completed, the foundation formed an integral raft-type composite foundation reinforcement. The total volume of the reinforced body is approximately 9696 m³ (the plane area of ​​the reinforced body is approximately 808.0 m², and the reinforcement depth is 12.0 m). Scope of composite foundation support: 15 composite foundation supports are designed at the four corners of the building and under the main load-bearing walls. The effective diameter of the irregular composite piles is not less than 3.0m, and the depth is 25.0m below the foundation base (the reinforcement range will be adjusted according to the on-site drilling conditions, and not less than 3.0m below the original pile base); the volume of the reinforced body is about 1377.0m3 (the effective diameter of the composite foundation support is about 3.0m, the length is 13.0m, and there are a total of 15 composite piles). Example 3 Please refer to Figures 4 and 5, which illustrate an engineering method for reinforcing and raising the foundation of a residential building to address settlement, using the reinforcement and raising scheme for residential building #16 as an example: I. Hole Position Layout Curtain reinforcement hole arrangement and depth: The holes are arranged outside the building foundation slab, with a spacing of about 2.5m between holes and a depth of 12.0m below the foundation slab (the actual hole positions and depths will be adjusted according to the actual site conditions). Reinforcement Hole Layout and Depth: Holes will be laid out indoors, with a tentative spacing of 3.3m, in a staggered pattern. Drilling will be vertical. For shallow reinforcement, the drilling depth will be approximately 4.0m below the foundation bottom, targeting the second layer of silt and the third layer of silty clay interbedded with silt. For deep reinforcement, the drilling depth will be 7.0m to 12m below the foundation bottom (entering the fifth layer of silt). Hole positions and depths should be adjusted based on actual site conditions, avoiding shear walls and CFG piles. The maximum hole spacing should not exceed 4.0m. (See the hole layout diagram for details.) Lifting hole arrangement: On the side of building settlement, some reinforcement holes will be used as lifting holes, with a hole depth of 4.0m to 7.0m below the foundation slab; if necessary, inclined holes will be drilled on the outside of the foundation slab or outdoors as lifting holes, with a drilling depth of approximately 4.0m to 7.0m below the foundation slab. (The location of outdoor and indoor lifting holes should be adjusted according to the actual site conditions). II. Scope of Reinforcement Curtain reinforcement scope: The curtain reinforcement scope extends 3.0m outward from the building foundation, and the reinforcement depth is 12.0m below the foundation slab. The volume of the reinforced body is approximately 5086m3 (total curtain length 141.3m, width 3.0m, height 12.0m). Shallow reinforcement scope: The reinforcement scope is the full area of ​​the raft foundation, with a planar area of ​​approximately 708.0 m2. The reinforcement depth is approximately 4.0 m below the foundation bottom. The reinforcement scope will be adjusted according to the on-site drilling conditions. Scope of deep reinforcement: The scope of planar reinforcement is the full area of ​​the raft foundation, with a planar area of ​​approximately 708.0 m2 and a reinforcement depth of 7.0 m to 12.0 m below the bottom of the raft foundation; The stable uplift range of the intermediate layer: The stable uplift layer is about 3.0m between the shallow reinforcement and the deep karst cave filling reinforcement layer. After the foundation lifting, correction, and reinforcement were completed, the foundation formed an integral raft-type composite foundation reinforcement. The total volume of the reinforced body is approximately 8496 m³ (the plane area of ​​the reinforced body is approximately 708.0 m², and the reinforcement depth is 12.0 m). Scope of composite foundation support: 15 composite foundation supports are designed at the four corners of the building and under the main load-bearing walls. The effective diameter of the irregular composite piles is not less than 3.0m, and the depth is 25.0m below the foundation base (the reinforcement range will be adjusted according to the on-site drilling conditions, and not less than 3.0m below the original pile base); the volume of the reinforced body is about 1285m3 (the effective diameter of the composite foundation support is about 3.0m, the length is 13.0m, and there are a total of 14 composite piles). Example 4 Please refer to Figures 6 and 7, which illustrate an engineering method for reinforcing and raising the foundation of a residential building to address settlement, using the reinforcement and raising scheme for residential building #17 as an example: I. Hole Position Layout Curtain reinforcement hole arrangement and depth: The holes are arranged outside the building foundation slab, with a spacing of about 2.5m between holes and a depth of 12.0m below the foundation slab (the actual hole positions and depths will be adjusted according to the actual site conditions). Reinforcement Hole Layout and Depth: Holes will be laid out indoors, with a tentative spacing of 3.3m, in a staggered pattern. Drilling will be vertical. For shallow reinforcement, the drilling depth will be approximately 4.0m below the foundation bottom, targeting the second layer of silt and the third layer of silty clay interbedded with silt. For deep reinforcement, the drilling depth will be 7.0m to 12m below the foundation bottom (entering the fifth layer of silt). Hole positions and depths should be adjusted based on actual site conditions, avoiding shear walls and CFG piles. The maximum hole spacing should not exceed 4.0m. (See the hole layout diagram for details.) Lifting hole arrangement: On the side of building settlement, some reinforcement holes will be used as lifting holes, with a hole depth of 4.0m to 7.0m below the foundation slab; if necessary, inclined holes will be drilled on the outside of the foundation slab or outdoors as lifting holes, with a drilling depth of approximately 4.0m to 7.0m below the foundation slab. (The location of outdoor and indoor lifting holes should be adjusted according to the actual site conditions). II. Scope of Reinforcement Curtain reinforcement scope: The curtain reinforcement scope extends 3.0m outward from the building foundation, and the reinforcement depth is 12.0m below the foundation slab. The volume of the reinforced body is approximately 6660m3 (total curtain length 185m, width 3.0m, height 12.0m). Shallow reinforcement scope: The reinforcement scope is the full area of ​​the raft foundation, with a planar area of ​​approximately 980.0 m2. The reinforcement depth is approximately 4.0 m below the foundation bottom. The reinforcement scope will be adjusted according to the on-site drilling conditions. Scope of deep reinforcement: The scope of planar reinforcement is the full area of ​​the raft foundation, with a planar area of ​​approximately 980.0 m2 and a reinforcement depth of 7.0 m to 12.0 m below the bottom of the raft foundation; The stable uplift range of the intermediate layer: The stable uplift layer is about 3.0m between the shallow reinforcement and the deep karst cave filling reinforcement layer. After the foundation lifting, correction, and reinforcement were completed, the foundation formed an integral raft-type composite foundation reinforcement. The total volume of the reinforced body is approximately 11,760 m³ (the plane area of ​​the reinforced body is approximately 980 m², and the reinforcement depth is 12.0 m). Scope of composite foundation support: 15 composite foundation supports will be designed at the four corners of the building and under the main load-bearing walls. The effective diameter of the irregular composite piles will be no less than 3.0m, and the depth will be 25.0m below the foundation base (the reinforcement range will be adjusted according to the on-site drilling conditions, and the depth below the original pile base will be no less than...). 3.0m); the volume of the reinforced body is about 1285m3 (the effective diameter of the composite foundation support is about 3.0m, the length is 13.0m, and there are a total of 14 composite piles). Working principle: The "shallow reinforcement and strengthening" and "intermediate layer reinforcement and lifting" are used to form a raft-type composite foundation, and the "deep composite foundation reinforcement support" forms a support body similar to a pile, so as to achieve the purpose of strengthening and lifting the building foundation and improve the overall stability and bearing capacity requirements of the building foundation. It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims. Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. An engineering method for reinforcing and lifting the foundation settlement of a residential building, characterized in that: Includes the following steps Step 1: Based on the differences in soil type, color, state, and inclusions, the strata within the exploration depth range are divided into layers; Step 2: Perform curtain wall grouting reinforcement construction around the building; form a curtain wall around the building foundation; Step 3: Shallow reinforcement and strengthening. The silty clay layer under the foundation slab is reinforced and strengthened to improve the density and rigidity of the foundation soil. Step 4: Deep reinforcement. Continue drilling down to the silty soil layer and begin the retreating layered reinforcement treatment of the original pile surrounding soil to increase the soil friction resistance around the pile and form an integral stone body. Step 5: After the shallow reinforcement layer and the deep reinforcement layer are completed, the soil is stably lifted in the intermediate base layer on the settlement side. The grouting pressure and grout ratio are adjusted on the settlement side, and the grout continuously fills and compacts the foundation soil layer. After the foundation reinforcement and lifting are completed, an integral raft composite foundation is formed. Step Six: Construct composite foundation reinforcement support structures. After the building reinforcement and lifting meet the requirements, construct multiple composite foundation reinforcement support structures at the bottom of the raft-type composite foundation.

2. The engineering method for reinforcing and lifting the foundation settlement of a residential building according to claim 1, characterized in that: In step one, the characteristics and distribution of the strata include: The first layer is a slightly dense silt layer: Yellowish-brown, moist, slightly dense, rapid shaking reaction, uniform soil texture, no luster reaction, low dry strength, low toughness, locally manifested as a loose silty thin layer, the surface layer is cultivated soil containing a small amount of plant roots, and the soil layer locally contains plastic silty clay. The second layer is a slightly denser silty clay layer: Yellowish-brown, moist, slightly dense, moderate shaking reaction, uniform soil texture, no luster reaction, low dry strength, low toughness, contains iron spots, mica flakes and ginger stone, locally high clay content, interbedded with thin layers or lenses of soft plastic to plastic silty clay. The third layer is a medium-dense silt layer: Yellowish-brown, moist, medium-dense, low dry strength, rapid shaking reaction, dull appearance, low toughness. Locally contains thin layers of silt with a high sand content; the main components are quartz and feldspar. This layer is discontinuous and locally pinches out. The fourth layer is a mixture of silt and silty clay: Yellowish-brown to brownish-gray, wet, slightly dense, moderate shaking reaction, dull reaction, low dry strength, low toughness, interlayered with thin layers or lenses of soft plastic to plastic silty clay. The fifth layer is a silt layer: Yellowish-brown, moist, slightly dense, low dry strength, moderate shaking reaction, no luster, low toughness. Locally mixed with a thin layer of powdery residue, containing a small amount of mica flakes and iron oxides; The sixth layer is a plastic silty clay layer: Grayish-brown, primarily plastic, with medium dry strength, no shaking reaction, moderate toughness, slightly glossy, containing small amounts of iron oxides, small ginger stones, calcareous nodules, snail debris, etc. Locally, it contains a medium-dense silty hard layer; The seventh layer is a fine sand layer: Yellowish-brown, saturated, dense, with a general particle size distribution. Its main mineral components are quartz and feldspar, containing iron and manganese, mica flakes, and occasionally snail fragments and small gingerstone. The eighth layer is a plastic-hard plastic silty clay layer: Brownish-yellow, plastic to hard plastic, medium dry strength, no shaking reaction, medium toughness, slightly glossy, contains a small amount of calcareous nodules, snail debris, etc., and locally contains a thin layer of medium-dense silt. The ninth layer is a fine sand layer.

3. The engineering method for reinforcing and raising the foundation settlement of a residential building according to claim 1, characterized in that: In step two, the skip-hole method is adopted for backward layered reinforcement. After each reinforcement section, the drill rod is pulled up 0.5 to 1.0m and the reinforcement continues. This cycle continues upward to the foundation slab. The holes for the curtain reinforcement are arranged on the outside of the foundation slab, and the curtain reinforcement range is extended outward from the building foundation.

4. The engineering method for reinforcing and raising the foundation settlement of a residential building according to claim 3, characterized in that: In steps two and three, the reinforcement holes are all arranged indoors and drilled vertically. The drilling depth for shallow reinforcement is 4.0m below the base plate, and the drilling depth for deep reinforcement is 7.0m to 12mm below the base plate. The scope of both shallow and deep reinforcement is the full area reinforcement of the base plate.

5. The engineering method for reinforcing and raising the foundation settlement of a residential building according to claim 1, characterized in that: In step five, the lifting holes are arranged by using some of the reinforcement holes as lifting holes on the side of the building settlement, and the hole depth is 4.0m to 7.0m below the foundation plate.

6. The engineering method for reinforcing and raising the foundation settlement of a residential building according to claim 1, characterized in that: In step five, a high-alumina iron composite grout is selected for grouting construction. The grout fills the voids in the foundation soil layer and solidifies to form a new structure.

7. The engineering method for reinforcing and raising the foundation settlement of a residential building according to claim 1, characterized in that: In step six, the scope of the composite foundation support body is the four corners of the building and under the main load-bearing walls.

8. The engineering method for reinforcing and raising the foundation settlement of a residential building according to claim 5, characterized in that: When performing grouting, the reinforcement grouting pressure is 0.3 to 1.2 MPa, and the lifting grouting pressure is 0.5 to 2.5 MPa.

9. The engineering method for reinforcing and raising the foundation settlement of a residential building according to claim 5, characterized in that: When performing grouting, the specific procedures include: Make positioning marks; drill vertically or at an angle; drill at the designated drilling point; After the drilling rig is in place, it should be leveled and centered, and the angle of the drill rod should be adjusted to align with the hole position. The drilling rig must not be moved after this. Before drilling, the concrete cover is removed, and the hole is drilled between adjacent reinforcing bars. Records are kept during drilling to provide reference data for grouting operations. The mixed slurry must be filtered through a screen before entering the grouting machine; Control the grouting pressure in each hole and observe the grout flow rate; Dust control for grouting materials is achieved by enclosing the site with barriers; grout diffusion is controlled by adjusting the grout mix ratio to control the grout's penetration capacity and setting speed; grouting pressure is controlled by constantly monitoring the ground dynamics and grouting pressure gauge readings. After grouting is completed, the opening is sealed and smoothed with cement mortar of the same or higher grade as the ground surface.

10. The engineering method for reinforcing and lifting the foundation settlement of a residential building according to claim 1, characterized in that: In step five, the lifting operation is carried out in an intermittent, cyclical manner, with a daily lifting height of less than 10 mm.

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