Reinforcement type foundation and reinforcement design method

Abstract

The invention relates to the technical field of buildings, in particular to a reinforced foundation and a reinforcement design method, and creatively solves the problem of inclination of an existing building or a building under construction on the basis of conceptual design, engineering experience summary and a large amount of computational analysis. The reinforcement design method comprises the following steps: investigating building conditions; geological exploration; monitoring deformation; a preliminary reinforcement treatment method is formed; optimizing, comparing and selecting the scheme; and implementing and verifying the effect. According to the foundation and the reinforcing design method, the overall rigidity of the foundation, the structure and the foundation is improved, the problem of differential settlement is solved, construction is flexible, construction can be conducted in a small-storey-height basement, and ground operation is not affected. The foundation comprises an original pile foundation, an original bottom plate, a jet grouting pile, grouting and a newly-added laminated slab. The key technology is that the existing foundation and foundation are fully utilized, and optimized, compared and selected high-quality design is adopted for deformation control and reinforcement. A new idea and a new technology are provided for solving the complex problem of rock and structural engineering, and the method has wide application prospects.

Description

Technical Field

[0001] This invention relates to the field of building technology, specifically to a reinforced foundation and reinforcement design method. Background Technology

[0002] In the construction industry, uneven settlement, tilting and cracking of the ground and walls are common engineering quality problems. These problems mostly stem from uneven foundation or insufficient foundation strength.

[0003] Taking a real-world project as an example, the Liangjia Affordable Housing Project in Benxi Taizihe New City, located in Liangjia Village, Mingshan District, Benxi City, comprises buildings 1-4. The main structures are 17-story high-rise residential buildings with shear wall structures, reaching a height of 51.20 meters, and include one basement level. During construction, all four buildings exhibited significant uneven ground settlement, wall cracking, and building tilting. In September 2013, the main structures of buildings 1, 3, and 4 were topped out. When the main structure of building 2 reached the 5th floor, significant floor tilting was discovered during internal wall construction, with large differences in the 500mm line measurements on the north and south sides, particularly noticeable on the ground floor, exceeding 40mm at its maximum. The difference gradually decreased above the 9th floor. The ground floor of buildings 3 and 4... After the rain, severe water accumulation occurred on the south side of the basement. Diagonal cracks also appeared in parts of the basement shear wall and first-floor walls on the south side of axis 9 of Building 3, caused by uneven settlement. Upon discovering the problem, the construction unit immediately suspended work and commissioned relevant units to investigate and handle the situation. Through on-site inspection and investigation, it was initially determined that the tilting and cracking were mainly caused by significant uneven settlement of the foundation. Based on this, a supplementary investigation, monitoring, and testing plan was formulated. Supplementary investigation and deformation monitoring clarified the site's geological conditions and the degree of karst development, monitored the development of building settlement and tilting, and concluded that the cause of the building's tilting and cracking was insufficient bearing capacity of the original bored pile foundation, leading to uneven pile settlement and consequently uneven foundation settlement.

[0004] Traditional treatment methods for such problems often have many limitations. For example, some methods are difficult to implement and have high requirements for site conditions, making them difficult to implement effectively in the interior space of basements with low floor heights. Some methods are costly and impose huge treatment expenses, placing a heavy economic burden on the project. Other methods are ineffective and cannot effectively control the uneven settlement of buildings, making it difficult to guarantee the long-term stability and safety of buildings.

[0005] In light of this, through long-term practice and in-depth research in handling numerous engineering quality accidents, our organization has developed an innovative reinforced foundation and design method. This method aims to effectively solve the problem of uneven settlement in buildings, overcome the shortcomings of traditional treatment methods, and provide a more reliable, efficient, and economical solution for ensuring the quality of building engineering. Summary of the Invention

[0006] To address the aforementioned problems, this invention provides a reinforced foundation and a reinforcement design method. This reinforced foundation and design method improves the overall rigidity of the foundation, structure, and substructure, solves the problem of uneven settlement, and offers flexible construction options, allowing for construction in low-rise basements without affecting above-ground operations.

[0007] The technical solution of the present invention is as follows: A reinforced foundation includes an original pile foundation, an original base slab, jet grouting piles, grouting, and a newly added composite slab; the original pile foundation is the existing building's pile foundation; the original base slab is the existing building's structural base slab; the jet grouting piles are jet grouting piles formed by high-pressure jet grouting under the original base slab, between the original pile foundations, and around the building's perimeter; the grouting is cement grout injected by pressure method under the original base slab, between the original pile foundations, and around the building's perimeter; and the newly added composite slab is a reinforced concrete raft slab installed on the original base slab.

[0008] The newly added composite slab is connected to the original base slab by additional reinforcement bars inside the original base slab to form an integral load-bearing component.

[0009] The newly added composite slab top reinforcement is embedded in the shear wall to form an integral load-bearing component.

[0010] A method for reinforcing and strengthening a foundation includes the following steps: S101: Investigate the building's tilt and cracks, make a preliminary determination of the cause of the tilt and cracking incidents, and formulate plans for pile foundation monitoring, geological exploration, and deformation monitoring. S102: Conduct pile foundation testing and geological surveys during the construction phase to determine the condition of the foundation and the bearing stratum at the pile tip; S103: Implement deformation monitoring and analyze the development trend of building settlement and tilt; S104: Based on the comprehensive investigation, survey and monitoring results, analyze the causes of building tilt and cracks, and formulate preliminary reinforcement treatment methods; S105: Through optimization and comparison of reinforcement design schemes, a reinforced foundation reinforcement scheme was selected; S106: Implement reinforcement design and continuously monitor and verify the effect.

[0011] The methods for analyzing the causes of building tilt and cracks in S104 include: combining pile foundation testing, geological survey results and deformation monitoring data to determine whether the bearing layer at the pile tip meets the design requirements, analyzing the uneven distribution of foundation soil layers, the development of dissolution fissures or karst caves, and the impact of construction process defects on the integrity of the pile body, and determining the dominant factors of uneven settlement.

[0012] The S105 reinforcement design scheme optimization comparison includes a combination of jet grouting pile composite foundation and newly added reinforced concrete composite slab. This scheme strengthens the foundation soil by grouting throughout the pile length and uses jet grouting piles to compensate for the insufficient bearing capacity of the original bored piles. At the same time, it forms an integral raft foundation by adding a reinforced concrete composite slab to the original base plate, thereby improving the overall rigidity of the foundation and coordinating uneven settlement.

[0013] In the combined reinforced concrete composite slab scheme of jet grouting pile foundation, at least two rows of jet grouting piles are added to the outside of the basement on the side of the building's tilt direction. The jet grouting piles and the extended part of the raft slab together form a pile-raft composite structure to control the building's tilt.

[0014] S106 includes foundation deformation calculation and adjustment, which adjusts the composite foundation stiffness according to the compressive strength grades of the original bored piles and jet grouting piles, and takes into account the increase in the deformation modulus of the foundation soil between piles after grouting reinforcement.

[0015] When analyzing the causes of building tilt in S104, the analysis includes the impact of frost heave on the foundation soil: when one side of the foundation trench is backfilled while the other side is not, the unidirectional frost heave force generated by the backfill soil on the building after the winter freeze-thaw will exacerbate the building tilt.

[0016] In S106, after the reinforcement design is implemented, the settlement of the building is continuously monitored until the tilt of each building reaches a stable state.

[0017] The beneficial effects of this invention are as follows: 1. The present invention discloses a reinforced foundation, wherein cement grout is injected under the original base slab, between the original pile foundations and the periphery using a pressure method to fill the void between the pile tip and the bearing layer of the original pile foundation, thereby increasing the strength of the bearing layer of the original pile foundation, reducing subsequent settlement, increasing the strength of the soil between the piles, and simultaneously improving the cohesion and integrity of the original pile foundation, jet grouting piles and the soil between the piles.

[0018] 2. The present invention discloses a reinforced foundation, wherein the original pile foundation and the soil between the piles reinforced by jet grouting and injection form a composite foundation of the original piles.

[0019] 3. The present invention discloses a reinforced foundation in which jet grouting piles are formed under the original base slab, between the original pile foundations and on the periphery using high-pressure jet grouting. The jet grouting pile composite foundation plays a supplementary and reinforcing role in bearing the original pile composite foundation.

[0020] 4. The present invention discloses a reinforced foundation in which the newly added composite slab is connected to the original base slab by roughening and embedding vertical steel bars, thereby strengthening the integrity of the new and old interfaces and improving the overall rigidity of the structural foundation.

[0021] 5. The present invention discloses a reinforced foundation in which the newly added composite slab is connected to the shear wall by roughening and anchoring with rebar, thereby enhancing the overall rigidity of the structure.

[0022] 6. The present invention discloses a reinforced foundation, which not only improves the bearing capacity and stiffness of the foundation, but also improves the overall stiffness of the structure and foundation. It has been verified by the treatment practice of multiple projects that it can effectively solve the problem of uneven settlement of buildings.

[0023] 7. The present invention discloses a reinforced foundation, which has construction flexibility and can be constructed in the interior space of a basement with a small floor height, without affecting the normal construction work of the above-ground part of the building.

[0024] 8. This invention discloses a reinforced foundation strengthening design method. This method, through a combination of jet grouting piles and newly added reinforced concrete composite slabs, effectively improves the overall stiffness of the foundation, coordinates uneven settlement, and enhances the overall stability of the structure. Its construction is flexible, adaptable to low-rise basement environments, and reduces the impact of construction on above-ground operations. By adding jet grouting piles and the extended portion of the raft slab to form a pile-raft combination, the building tilt is effectively controlled. Compared with traditional methods, this design method is economical and reasonable, reducing treatment costs. Continuous monitoring verifies the strengthening effect, ensuring the long-term stability of the building. Furthermore, by comprehensively analyzing the causes of building tilt, the root cause of the problem is accurately located, and the impact of frost heave on the foundation soil is considered, further improving the rationality and comprehensiveness of the design. Attached Figure Description

[0025] The solutions and advantages of this application will become clear to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of the invention.

[0026] In the attached diagram: Figure 1-1 This is one of the plan layout diagrams of the original pile foundation for a reinforced foundation according to an embodiment of the present invention; Figure 1-2 This is a second plan layout diagram of the original pile foundation of a reinforced foundation according to an embodiment of the present invention; Figure 2-1 This is one of the plan views of a jet grouting pile and grouting foundation reinforcement method for a reinforced foundation according to an embodiment of the present invention; Figure 2-2 This is a second plan view of a jet grouting pile and grouting foundation reinforcement method for a reinforced foundation according to an embodiment of the present invention. Figure 3-1This is one of the plan layout diagrams of the newly added composite slab in a reinforced foundation according to an embodiment of the present invention; Figure 3-2 This is a second plan layout diagram of the newly added composite slab in a reinforced foundation according to an embodiment of the present invention; Figure 4 This is a schematic diagram illustrating the construction method of adding a composite slab to a reinforced foundation according to an embodiment of the present invention. Figure 5 This is a schematic diagram of the newly added composite slab and external wall rebar anchoring in a reinforced foundation according to an embodiment of the present invention. The components represented by the various reference numerals in the diagram are: This invention comprises: 1. a cushion layer; 2. the original base slab; 3. reinforcing bars inside the original base slab; 4. the top surface of the original base slab; 5. additional reinforcing bars inside the original base slab; 6. the top reinforcing bars of the newly added composite slab; 7. the newly added composite slab; and 8. the bottom of the shear wall. Detailed Implementation Example

[0027] The new reinforced foundation consists of the original pile foundation, the original base slab 2, jet grouting piles, grouting, and the newly added composite slab 7.

[0028] The original pile foundation is the pile foundation of the existing building, see [link / reference]. Figure 1-1 , Figure 1-2 .

[0029] Original base slab 2 is the existing building's structural base slab, see [link / reference] Figure 4 and Figure 5 A padding layer 1 is provided below the original base plate 2.

[0030] Jet grouting piles are jet grouting piles formed by high-pressure jet grouting under the original base slab, between the original pile foundations, and around the building perimeter. The spacing and location of the jet grouting piles are determined by calculation. Holes are drilled in the original base slab according to the new pile locations, and jet grouting piles are constructed by aligning the high-pressure jet grouting pile machine with the drilled holes. For areas where the bearing layer of the original pile foundation has poor strength or contains voids such as karst caves, a combination of jet grouting and grouting is used. That is, low-pressure grouting is first performed to fill the voids between the pile end of the original pile foundation and the bearing layer at the pile end, and then high-pressure jet grouting piles are constructed.

[0031] Grouting is a cement grout injected under the original foundation slab 2, between the original pile foundations, and around the building using a pressure method. Its function is to fill the gap between the pile tip and the bearing layer of the original pile foundation, improve the strength of the bearing layer of the original pile foundation, improve the strength of the soil between the piles, and at the same time improve the cohesion and integrity of the original pile foundation, jet grouting piles, and soil between the piles, forming a composite foundation with enhanced stiffness.

[0032] The newly added composite slab 7 is a reinforced concrete raft slab set on the original base slab 2. The newly added composite slab 7 is connected to the original base slab 2 through additional reinforcing bars 7 inside the original base slab. At the same time, the top reinforcing bars 6 of the newly added composite slab are inserted into the bottom 8 of the shear wall to form an integral load-bearing component, which strengthens the integrity of the old and new interfaces and improves the overall stiffness of the structural foundation.

[0033] Because the original pile foundation's single pile bearing capacity did not meet the design requirements, it caused uneven settlement of the building. Through innovative design, the bearing capacity of the original pile foundation was reduced according to the stiffness distribution principle, forming a composite foundation between the original piles and the soil between the piles reinforced by jet grouting and injection. At the same time, the newly added jet grouting pile composite foundation supplemented the bearing capacity of the original pile composite foundation. The two worked together to improve the overall strength and stiffness of the foundation. The problem of inconsistent bearing capacity and deformation between the two types of piles can be coordinated by the raft foundation formed by the original base slab 2 and the newly added composite slab 7. Example

[0034] Based on conceptual design, engineering experience summarization, and extensive calculation and analysis, a creative design method for solving the tilting problem of existing or under-construction buildings is proposed. The key technology is to make full use of the existing foundation and use optimized and selected high-quality designs for deformation control and reinforcement. This provides new concepts and technologies for solving complex geotechnical and structural engineering problems and has broad application prospects. The main innovative technical work and achievements are as follows: S101: Based on the investigation of the building's tilt and cracks, it was initially determined that the tilt and cracking accidents were mainly caused by large uneven settlement of the foundation. Based on this, a plan for pile foundation monitoring, geological investigation during construction, and deformation monitoring was formulated. S102: Conduct pile foundation testing and geological surveys during the construction phase to ascertain the foundation conditions, especially the bearing stratum at the pile tip; S103: Conduct deformation monitoring to track the settlement and tilting trends of buildings; S104: Based on the above investigation, survey and monitoring results, analyze the causes of the building tilting and cracks and formulate preliminary reinforcement methods; S105: Compare and optimize reinforcement design schemes, and finally select a creative reinforcement-type foundation reinforcement design method; S106: Design, implement, and continuously monitor and verify the effectiveness of the reinforcement design.

[0035] Step S104, the specific content of which is as follows: The designed bearing layer of the piles for Building 2 is a pebble layer, while the designed bearing layer of the piles for Buildings 1, 3, and 4 is limestone. Deformation monitoring results show that the buildings exhibit uneven settlement. By investigating the construction of bored piles and combining the pile foundation testing and geological surveys conducted during the construction phase to determine the bearing layer of the piles, the causes of uneven settlement in the buildings were analyzed. ①The design of buildings 1#, 3# and 4# uses moderately weathered limestone as the bearing layer for pile ends. The bored piles are constructed using pneumatic picks. This technology has poor rock penetration ability. In addition, the groundwater is abundant, which results in the pile ends only sitting on the strongly weathered rock layer and failing to enter the moderately weathered rock layer required by the design. Furthermore, the pile bottom is not enlarged. The low-strain measured signal waveform diagram of the pile integrity test showed that most of the piles showed obvious positive pile bottom reflection, which was completely different from the interface reflection of the rock-embedded enlarged piles embedded in moderately weathered bedrock. This indicates that there is concrete segregation at the pile bottom or the enlarged head is not obvious, which also verifies the above analysis. ② Supplementary investigation revealed that the strong weathered limestone layer where the actual pile ends are located has low strength, well-developed dissolution fissures, and localized karst caves, which are unevenly distributed. The dissolution fissures of the strong weathered limestone at the pile ends of buildings 1, 3, and 4 are well-developed and have formed karst caves. Regardless of the degree of filling, the bearing capacity of the karst caves cannot meet the design requirements. Therefore, buildings 1, 3, and 4 all showed that the settlement on the southwest side was greater than that on the northeast side. ③ During the excavation of Building 2, a saturated pebble layer was encountered. When manually excavating the hole, dewatering was carried out inside the hole. Due to the abundant water, it was difficult to excavate. The design was adjusted to make the bearing layer of the pile tip a pebble layer. When the structure was built to the 5th floor, a slight tilt was found. Based on the monitoring results, it was found that the pile tip was not enlarged during the actual construction. In addition, it was affected by the uneven distribution of strong weathered limestone karst fissures and caves below. Therefore, Building 2 also experienced uneven settlement. ④ The foundation soil was subjected to frost heave. During the construction of the building, the north side of the basement trench was backfilled, while the south side was not. After experiencing the winter freeze-thaw cycle, the backfill soil on the north side exerted a frost heave force on the building from north to south. According to the monitoring results, the horizontal displacement of the four buildings from north to south reached 115mm-240mm respectively. The buildings were already experiencing uneven settlement due to the foundation problems, and the addition of the horizontal force from north to south caused the buildings to tilt severely from northeast to southwest.

[0036] Step S105, the specific content of which is as follows: Analysis of the causes of the building's structural defects revealed that the accident was due to a significantly low actual bearing capacity of the piles and uneven bearing capacity of the pile tip bearing layer, causing the building to tilt to one side. To solve this problem, the bearing capacity of the foundation should first be increased to compensate for the insufficient bearing capacity of the original foundation. Furthermore, to reduce foundation deformation, the foundation stiffness needs to be enhanced, increasing the overall deformation modulus of the foundation. Only by simultaneously improving the foundation stiffness can the later-stage settlement of the building be controlled. Based on the above conceptual design, the following three foundation treatment schemes were compared and selected. (1) Grouting method is adopted to reinforce the soil between the original bored piles; ① The grouting pipe is inserted into the foundation through a borehole, but the grouting hole requires an exploration rotary drilling rig. The existing exploration drilling rig is limited by the height of the basement (2.9m) and cannot be operated. ②The grouting reinforcement effect is poor because the gravel layer at the pile tip is saturated; ③ Due to significant variations in the foundation soil layers, grouting reinforcement may not achieve the desired effect as expected; ④ Grouting method cannot control the tilt of the building; ⑤ This plan has a low cost.

[0037] (2) The load is jointly borne by precast concrete (or steel) piles under static pressure; ①Since the pebble layer is buried at a depth of about 4m, which is relatively shallow, it is still necessary to drill to the designed depth, which is quite difficult; ② The opening diameter is not less than 150mm, which causes significant damage to the original foundation slab reinforcement; ③ Static pressure pile construction requires sufficient pile driving reaction force, and the narrow basement space makes construction more difficult; ④ This plan has a long construction period, with each building requiring 40 days for pile driving alone, and a total construction period of 160 days for the four buildings; ⑤ This plan is expensive, requiring approximately 2 million yuan per building, for a total of 8 million yuan.

[0038] Scheme of jet grouting piles + foundation grouting + addition of reinforced concrete composite slabs; ① This solution is highly feasible and can be implemented flexibly in the narrow space of a basement; ② The grouting process reinforces the foundation soil (original soil between piles) throughout the pile length, thereby increasing the foundation stiffness; ③ The diameter of the jet grouting pile hole can be controlled within 100mm, no drilling rig is required for pre-drilling, and the hole position can avoid the bottom slab reinforcement; ④ The jet grouting pile composite foundation can strengthen the original bored piles to compensate for insufficient bearing capacity. ⑤ Improve the overall rigidity of the foundation, control the overall foundation deformation, and prevent the building from continuing to tilt; ⑥ By adding a reinforced concrete composite slab to the original structural base slab, a new raft foundation can be formed together with the original base slab, which can improve the overall rigidity of the foundation and coordinate uneven settlement of the foundation. ⑦ Two rows of jet grouting piles are added to the outside of the basement on the side of the building's tilt direction to form a pile-raft combination with the outward expansion of the raft slab, which can help control the building's tilt. ⑧ The construction period is short. Each building requires 20 days for jet grouting and soil grouting between the piles, and a total of 80 days for the four buildings. ⑨ This plan has a low construction cost, requiring approximately 1 million yuan per building, for a total of 4 million yuan.

[0039] Step S106, the specific content of which is as follows: ① Use of the original bored pile bearing capacity In response to issues such as uneven pile tip bearing stratum, localized severe weathering, breakage, and karst caves, the bearing capacity of the original bored pile was recalculated, and its usability was determined in conjunction with monitoring data. ② Foundation deformation calculation and adjustment The value of the foundation deformation modulus is determined based on the compressive strength grades of the new and old pile reinforcements (C30 for bored piles and C10 for jet grouting piles) to adjust the stiffness of the composite foundation. After grouting reinforcement, the compression (deformation) modulus of the foundation soil between piles is significantly improved, and the deformation modulus of the upper miscellaneous fill, silty clay and silt can be increased to more than 10MPa. ③ Design jet grouting piles to compensate for the insufficient bearing capacity of the original bored piles, and share the load with the original bored piles to meet the building load requirements; ④ Design a reinforced concrete composite slab, which is combined with the original structural slab to form an integral raft slab, thereby improving the overall foundation rigidity and playing a role in coordinating uneven settlement of the foundation. ⑤ After reinforcement treatment, settlement monitoring was carried out on the buildings. The tilt of Building 1 finally stabilized at 3.5‰, the tilt of Building 2 finally stabilized at 3.0‰, the tilt of Building 3 finally stabilized at 2.3‰, and the tilt of Building 4 finally stabilized at 4.1‰. Settlement monitoring results show that the uneven settlement of the building was well controlled after reinforcement treatment, and the building no longer tilted.

Claims

1. A reinforced foundation, characterized in that, Including the original pile foundation, the original bottom slab (2), jet grouting piles, grouting and newly added composite slab (7); the original pile foundation is the existing building pile foundation; The original base slab (2) is the existing building structure base slab; the jet grouting pile is a jet grouting pile body formed by high pressure jet grouting under the original base slab, between the original pile foundations and outside the building; Grouting is cement grout injected under the original base slab, between the original pile foundations and around the building using a pressure method; the newly added composite slab (7) is a reinforced concrete raft slab set on the original base slab (2).

2. The reinforced foundation according to claim 1, characterized in that, The newly added composite slab (7) is connected to the original base plate (2) through additional reinforcement bars (5) inside the original base plate to form an integral load-bearing component.

3. The reinforced foundation according to claim 1, characterized in that, The newly added composite slab (7) top reinforcement (6) is implanted into the shear wall to form an integral load-bearing component.

4. A method for reinforcing and strengthening a foundation, characterized in that, Includes the following steps: S101: Investigate the building's tilt and cracks, make a preliminary determination of the cause of the tilt and cracking incidents, and formulate plans for pile foundation monitoring, geological exploration, and deformation monitoring. S102: Conduct pile foundation testing and geological surveys during the construction phase to determine the condition of the foundation and the bearing stratum at the pile tip; S103: Implement deformation monitoring and analyze the development trend of building settlement and tilt; S104: Based on the comprehensive investigation, survey and monitoring results, analyze the causes of building tilt and cracks, and formulate preliminary reinforcement treatment methods; S105: Through optimization and comparison of reinforcement design schemes, a reinforced foundation reinforcement scheme was selected; S106: Implement reinforcement design and continuously monitor and verify the effect.

5. The reinforcement design method for a reinforced foundation according to claim 4, characterized in that, The method for analyzing the causes of building tilt and cracks in S104 includes: combining pile foundation testing, geological survey results and deformation monitoring data to determine whether the bearing layer at the pile tip meets the design requirements, analyzing the uneven distribution of foundation soil layers, the development of dissolution fissures or karst caves, and the impact of construction process defects on the integrity of the pile body, and determining the dominant factors of uneven settlement.

6. The reinforcement design method for a reinforced foundation according to claim 4, characterized in that, The optimization comparison of the reinforcement design schemes in S105 includes a scheme combining jet grouting pile composite foundation with newly added reinforced concrete composite slab. This scheme strengthens the foundation soil by grouting throughout the pile length and uses jet grouting piles to compensate for the insufficient bearing capacity of the original bored piles. At the same time, it forms an integral raft foundation by adding a reinforced concrete composite slab to the original base plate, thereby improving the overall rigidity of the foundation and coordinating uneven settlement.

7. The reinforcement design method for a reinforced foundation according to claim 6, characterized in that, In the proposed composite foundation scheme of jet grouting piles combined with newly added reinforced concrete composite slab, at least two rows of jet grouting piles are added to the outside of the basement on the side of the building's tilt direction. The jet grouting piles and the extended portion of the raft slab together form a pile-raft composite structure to control the building's tilt.

8. The reinforcement design method for a reinforced foundation according to claim 4, characterized in that, S106 includes foundation deformation calculation and adjustment, which involves adjusting the composite foundation stiffness based on the compressive strength grades of the original bored piles and jet grouting piles, and taking into account the increase in the deformation modulus of the foundation soil between piles after grouting reinforcement.

9. The reinforcement design method for a reinforced foundation according to claim 4, characterized in that, When analyzing the causes of building tilt in S104, the analysis includes the impact of frost heave on the foundation soil: when one side of the foundation trench is backfilled while the other side is not, the unidirectional frost heave force generated by the backfill soil on the building after the winter freeze-thaw will exacerbate the tilt of the building.

10. The reinforcement design method for a reinforced foundation according to claim 4, characterized in that, In step S106, after the reinforcement design is implemented, the settlement of the building is continuously monitored until the tilt of each building reaches a stable state.

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