Grouting, tilt rectification, and lifting method for raft foundation buildings

Abstract

Disclosed in the present application is a grouting, tilt rectification, and lifting method for raft foundation buildings. In the present application, taking the center point of a building as the origin, settlement monitoring points are arranged in the shape of the Chinese character "米" along axes corresponding to different directions, which can clearly reflect the displacement and settlement situation of points at the edges of and within the building, thus avoiding the occurrence of raft cracking or deformation caused by neglect of the interior of the building during lifting; holes are arranged obliquely and in rows on the basis of the settlement and tilt situation of the building, and each row of lifting holes is parallel to the boundary line between a primary lifting area and a secondary lifting area, making the positioning of the lifting holes more convenient, accelerating the construction progress, and improving construction efficiency. The building is subjected to area-by-area grouting and lifting, and changes in displacement value of lifting monitoring points are observed as lifting is performed, enabling the overall lifting situation and effect to be observed more directly and conveniently during lifting of the building and making the grouting and lifting process easier to control, thus avoiding structural damage and grout waste caused by excessive lifting, accelerating the construction progress, and improving construction quality.

Description

A grouting method for tilt correction and lifting of raft foundation structures Technical Field

[0001] This application relates to the field of building foundation reinforcement and lifting technology, and in particular to a grouting method for correcting tilting and lifting raft foundation buildings. Background Technology

[0002] The construction of high-rise buildings is increasing daily, leading to increasingly serious problems such as uneven settlement of structures. Grouting correction and lifting technology can effectively raise the ground level, offering advantages such as economy, efficiency, and environmental friendliness, and is widely used in building tilt correction projects. However, current grouting correction technologies only lift based on settlement displacement changes at monitoring points on the building's edge, failing to reflect internal settlement changes. This results in frequent cracking or deformation of the raft slab during the lifting process. Furthermore, the amount of grout injected is difficult to control during grouting, easily leading to over-lifting, structural damage, grout waste, and delays in construction. Therefore, we have invented a novel grouting correction and lifting method for buildings. Summary of the Invention

[0003] This application provides a grouting correction and lifting method for raft foundation structures, which solves the technical problems such as the inability to monitor the internal lifting of raft foundation structures in real time during the grouting and lifting process, which leads to easy deformation and cracking of the raft foundation and structural damage, and the difficulty in controlling the grouting volume, resulting in grout waste and affecting the construction progress.

[0004] To achieve the above objectives, this application adopts the following technical solution:

[0005] This application provides a grouting method for correcting tilting and lifting raft foundation structures, comprising the following steps:

[0006] Step 1: Set up settlement monitoring points: On the top of the building, with the center of the building as the origin, set up settlement monitoring points at intervals along the north-south, east-west, northwest-southeast, and northeast-southwest axes of the origin, so that the settlement monitoring points are generally distributed in a star shape, and record the displacement of the settlement monitoring points.

[0007] Step 2: Calculate the settlement tilt rate of the building in different directions: Based on the displacement data of the settlement monitoring points and the horizontal distance of the building structure, calculate the settlement tilt rate of the building in different directions.

[0008] Step 3: Determine the primary and secondary uplift zones: Based on the calculated settlement inclination rates of the building in different directions, determine the primary and secondary uplift zones, and use the axis corresponding to the direction with the minimum settlement inclination rate as the boundary line between the primary and secondary uplift zones.

[0009] Step 4: Grouting to form a shallow foundation protective layer: Grouting under the raft foundation to form a shallow foundation protective layer can improve the soil strength and stiffness in this area, so as to make the bottom of the raft foundation more stress-coordinated.

[0010] Step 5: Arrange lifting holes: Arrange multiple rows of spaced lifting holes diagonally on the surface of the raft slab, with the lines connecting each row of lifting holes parallel to the boundary line between the main lifting area and the secondary lifting area.

[0011] Step 6, Set up lifting monitoring points: Determine the orthographic projection of the lifting hole on the top of the building as the lifting monitoring point, and record the instantaneous displacement of the area where the lifting hole is located during lifting;

[0012] Step 7, grouting and tilt correction and lifting, includes: the grouting and lifting sequence starts from the position with the largest settlement in the main lifting area, and proceeds along the axis corresponding to the direction of the largest settlement inclination, until it reaches the position with the smallest settlement in the secondary lifting area; during grouting and lifting, the displacement changes of the lifting monitoring points are observed while grouting and lifting.

[0013] Preferably, in step two, the method for calculating the settlement inclination rate is as follows: for one of the axes along the origin in the north-south, east-west, northwest-southeast, and northeast-southwest directions, obtain the displacement difference between the settlement monitoring points at both ends of the building on that axis, and divide the obtained displacement difference by the horizontal distance between the settlement monitoring points at both ends to obtain the settlement inclination rate in that axis direction.

[0014] Preferably, the settlement of the main uplift zone is greater than that of the secondary uplift zone.

[0015] Preferably, in step seven, during grouting and lifting, the first row of grouting holes is designated as J1, the second row as J2, and so on, with the nth row of grouting holes designated as Jn. First, grouting and lifting are performed on J1, and the lifting displacement of the area corresponding to J1 is observed continuously. Grouting is stopped when the horizontal height of the area corresponding to J1 approaches the horizontal height of the area corresponding to J2. Then, grouting is performed on J1 and J2 simultaneously, and the lifting changes of the areas corresponding to J1 and J2 are observed continuously. Grouting is stopped when the horizontal height of the areas corresponding to J1 and J2 approaches the horizontal height of the area corresponding to J3, and so on. Grouting is stopped when the horizontal height of the areas corresponding to J1, J2, ..., J(n-1) approaches the horizontal height of the area corresponding to Jn. When the settlement and tilt rates of the building in all directions meet the requirements, the tilt correction and lifting work of the building is completed.

[0016] Preferably, the method further includes transmitting the displacement information of the monitoring points obtained by sensors deployed at the settlement monitoring points and the heave monitoring points to the monitoring system.

[0017] Preferably, the geological structure of the building includes a backfill layer, a gravel layer, a foundation bearing layer, and a raised layer, with the gravel layer located on the upper surface of the foundation bearing layer and the backfill layer located on the upper surface of the gravel layer.

[0018] Preferably, the lower part of the raised layer is set in the bearing layer of the foundation, and the upper part is set in the pebble layer. A shallow foundation protection layer is set on the upper surface of the raised layer, and the shallow foundation protection layer is set in the pebble layer. A raft slab is set on the upper surface of the shallow foundation protection layer.

[0019] Preferably, the lower end face of the raft foundation is flush with the interface between the backfill soil layer and the gravel layer, and a building is set on the upper end face of the raft foundation; the upper end face of the backfill soil layer extends beyond the upper end face of the raft foundation.

[0020] Preferably, the edge of the raised layer is flush with the edge of the shallow foundation protective layer, the edge of the shallow foundation protective layer extends beyond the edge of the raft slab, and the edge of the raft slab extends beyond the edge of the building.

[0021] Preferably, in step seven, after the shallow foundation protective layer reaches the design strength, grouting and lifting are carried out. The grouting pipe is inserted into the lifting hole, and grouting and lifting are carried out below the shallow foundation protective layer to construct a lifting layer on the lower end face of the shallow foundation protective layer, thereby forming a supporting effect.

[0022] The beneficial effects of this application are reflected in:

[0023] 1) In this application, the settlement monitoring points are arranged in a star shape along the axis corresponding to different directions with the center point of the building as the origin. This can clearly reflect the displacement and settlement of the building's edge and interior points, and avoid the situation where the interior of the building is ignored during the lifting process, which may lead to cracking or deformation of the raft slab.

[0024] 2) In this application, the main lifting area and the secondary lifting area are determined according to the magnitude of the settlement tilt rate of the building in different directions, which more clearly reflects the settlement of the building and provides convenient conditions for lifting.

[0025] 3) In this application, the holes are arranged in an oblique pattern according to the settlement and tilt of the building. Each row of lifting holes is parallel to the dividing line between the main and secondary lifting areas, which makes the positioning of the lifting holes more convenient, speeds up the construction progress, and improves the construction efficiency.

[0026] 4) In this application, the building is grouted and lifted in sections, and the changes in the displacement values ​​of the lifting monitoring points are observed while the building is being lifted. This makes it easier to observe the overall lifting situation and effect more intuitively and conveniently. The grouting and lifting process is easier to control, avoiding excessive lifting that could cause structural damage and waste of grout, thus accelerating the construction progress and improving the construction quality.

[0027] Other features and advantages of this application will be set forth in the following description and will be apparent in part from the description or may be learned by practicing the application; the main objectives and other advantages of this application may be realized and obtained by means of the embodiments particularly pointed out in the description. Attached Figure Description

[0028] Figure 1 is a diagram showing the layout of settlement monitoring points in an embodiment of this application.

[0029] Figure 2 is a schematic diagram of the primary and secondary lifting areas in an embodiment of this application.

[0030] Figure 3 is a schematic diagram of the shallow base protection layer in an embodiment of this application.

[0031] Figure 4 is a diagram showing the arrangement of lifting holes in an embodiment of this application.

[0032] Figure 5 is a schematic diagram of grouting correction and lifting in an embodiment of this application.

[0033] Figure 6 is a plan view of the grouting correction and lifting area in an embodiment of this application.

[0034] Reference numerals: 1. Building; 2. Raft foundation; 3. Shallow foundation protective layer; 4. Backfill layer; 5. Gravel layer; 6. Bearing layer of foundation; 7. Uplift layer. Detailed Implementation

[0035] The technical solutions of this application are described in detail below through embodiments. The following embodiments are merely exemplary and can only be used to explain and illustrate the technical solutions of this application, and should not be construed as limiting the technical solutions of this application.

[0036] Example:

[0037] This embodiment takes the reinforcement and lifting project of a rectangular building 1 as an example. The building 1 is 20m long, 15m wide and 85m high. It is based on a raft foundation 2 and the bearing layer is a pebble layer 5 with high porosity. There are plastic to soft plastic silty clays of different thicknesses near or below the bearing layer. The characteristic value of the foundation bearing capacity is about 75kPa to 200kPa. Insufficient foundation bearing capacity leads to uneven settlement.

[0038] Step 1: Set up settlement monitoring points: Set up settlement monitoring points on the top of building 1 in a star pattern along the axes a-a' (north-south), b-b' (east-west), c-c' (northwest-southeast), and d-d' (northeast-southwest), as shown in Figure 1. Record the displacements of the settlement monitoring points as shown in Tables 1, 2, 3, and 4.

[0039] Table 1. Settlement displacement (mm) at settlement monitoring points along axis a-a'

[0040] Table 2 Settlement displacement (mm) at settlement monitoring points along axis b-b'

[0041] Table 3 Settlement displacement (mm) at settlement monitoring points along axis c-c'

[0042] Table 4 Settlement displacement (mm) at settlement monitoring points along axis d-d'

[0043] Step 2: Calculate the settlement tilt rate of building 1 in different directions. Based on the settlement displacement data of the settlement monitoring points and the horizontal distance between the settlement monitoring points (see Tables 1, 2, 3, 4, and Figure 1), calculate the settlement tilt rate of building 1 in different directions. The calculation method for the settlement tilt rate is as follows: Subtract the displacements of the settlement monitoring points at both ends of a certain axis of building 1, and divide the difference by the horizontal distance between the two settlement monitoring points.

[0044] K a-a’ =(99.25-46.23) / 15 = 3.53‰

[0045] K b-b’ =(98.57-40.62) / 20 = 2.90‰

[0046] K c-c’ =(75.32-69.80) / 25 = 0.22‰

[0047] K d-d’ =(115.26-12.13) / 25 = 4.13‰

[0048] Step 3: Determine the primary and secondary uplift zones: Based on the calculated settlement tilt rate K of building 1 in different directions. a K b K c K d The magnitude of the settlement is used to determine the main uplift zone and the secondary uplift zone; the main uplift zone is the area with large settlement, and the secondary uplift zone is the area with relatively small settlement. Here, the axis c-c' corresponding to the direction of minimum settlement inclination is used as the dividing line between the main uplift zone and the secondary uplift zone, as shown in Figure 2.

[0049] Step 4, Grouting to form shallow foundation protective layer 3: Grouting is performed within a 3m range below the foundation to form shallow foundation protective layer 3, which can improve the soil strength and stiffness in this area, make the foundation slab stress coordinated, ensure the uniformity of the lifting effect, avoid the hidden dangers of secondary tilting or foundation cracking of building 1 due to excessive local lifting, and better ensure the lifting effect.

[0050] Furthermore, the method provided in this embodiment is based on building 1 and the geological structure, wherein the geological structure includes a backfill layer 4, a gravel layer 5, a foundation bearing layer 6, and a raised layer 7. The gravel layer 5 is disposed on the upper end face of the foundation bearing layer 6, and the backfill layer 4 is disposed on the upper end face of the gravel layer 5. The lower part of the raised layer 7 is disposed in the foundation bearing layer 6, and the upper part is disposed in the gravel layer 5. A shallow foundation protection layer 3 is disposed on the upper end face of the raised layer 7. The shallow foundation protection layer 3 is disposed in the gravel layer 5, and a raft slab 2 is disposed on the upper end face of the shallow foundation protection layer 3. The lower end face of the raft slab 2 is flush with the interface between the backfill layer 4 and the gravel layer 5, and building 1 is disposed on the upper end face of the raft slab 2. The upper end face of the backfill layer 4 extends beyond the upper end face of the raft slab 2. The edge of the raised layer 7 is flush with the edge of the shallow foundation protection layer 3, the edge of the shallow foundation protection layer 3 extends beyond the edge of the raft slab 2, and the edge of the raft slab 2 extends beyond the edge of building 1; see Figure 3.

[0051] Step 5, Arrange lifting holes: Multiple rows of lifting holes are arranged diagonally on the surface of raft 2. The lines connecting each row of lifting holes are parallel to the boundary line between the main lifting area and the secondary lifting area. According to the diagonal lifting sequence, they are divided into holes 1, 2, 3, 4, 5, 6, 7, 8, and 9. Starting from the position with the largest settlement in the main lifting area, the holes advance along the axis d-d' corresponding to the direction of the largest settlement inclination, approaching the position with the smallest settlement in the secondary lifting area, as shown in Figure 4.

[0052] Step 6, Set up lifting monitoring points: Determine the orthographic projection of the lifting hole on the top of building 1 as the lifting monitoring point, and record the instantaneous displacement of the area where the lifting hole is located during lifting;

[0053] Step 7, Grouting and Lifting: After the shallow foundation protective layer 3 reaches its design strength, grouting and lifting are carried out. The grouting pipe is inserted into the lifting hole, and grouting and lifting are performed below the shallow foundation protective layer 3 to construct a lifting layer 7 on the lower end face of the shallow foundation protective layer 3 to form a supporting effect. During lifting, the displacement change is observed while lifting. Let the first row of grouting holes be J1, the second row of grouting holes be J2, and so on, with the nth row of grouting holes being Jn. First, grouting and lifting are performed on J1, and the lifting displacement change of the area corresponding to J1 is observed at any time. When the horizontal height of the area corresponding to J1 is close to the horizontal height of the area corresponding to J2, grouting is stopped. Then, grouting is performed on J1 and J2 simultaneously, and the lifting change of the areas corresponding to J1 and J2 is observed at any time. When the horizontal height of the areas corresponding to J1 and J2 is close to the horizontal height of the area corresponding to J3, grouting is stopped... and so on, until the horizontal height of the areas corresponding to J1, J2...Jn-1 is close to the horizontal height of the area corresponding to Jn, grouting is stopped.

[0054] In this embodiment, the specific operation process is as follows: First, grouting is performed on hole 1 to raise it, and the changes in the raising of the area corresponding to hole 1 are observed at any time. Grouting is stopped when the horizontal height of the area corresponding to hole 1 approaches the horizontal height of the area corresponding to hole 2. Next, grouting is performed on holes 1 and 2 simultaneously, and the changes in the raising of the areas corresponding to holes 1 and 2 are observed at any time. Grouting is stopped when the horizontal height of the areas corresponding to holes 1 and 2 approaches the horizontal height of the area corresponding to hole 3. Then, grouting is performed on holes 1, 2, and 3 simultaneously, and the changes in the raising of the areas corresponding to holes 1, 2, and 3 are observed at any time. Grouting is stopped when the horizontal height of the areas corresponding to holes 1, 2, and 3 approaches the horizontal height of the area corresponding to hole 4. At this time, the settlement inclination rate in each direction meets the requirements, and the settlement in each area is close to leveling, as shown in Figures 5 and 6. In Figure 5, the horizontal direction represents the raised hole, the vertical direction represents the magnitude of the settlement displacement, and the arrow indicates grouting.

[0055] Furthermore, in this embodiment, a monitoring system is also included, in which sensors are deployed at both settlement monitoring points and uplift monitoring points to transmit the displacement of the monitoring points to the monitoring system for real-time monitoring.

[0056] The above description is only a preferred embodiment of this application, but the protection scope of this application is not limited thereto. Any changes or substitutions that can be conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the protection scope of this application.

Claims

1. A grouting method for correcting tilting and lifting raft foundation structures, characterized in that, Includes the following steps: Step 1: On the top of the building (1), with the center of the building (1) as the origin, settlement monitoring points are arranged at intervals along the north-south, east-west, northwest-southeast and northeast-southwest axes of the origin, so that the settlement monitoring points are generally distributed in a star shape, and the displacement of the settlement monitoring points is recorded. Step 2: Based on the displacement data of the settlement monitoring points and the horizontal distance of the building (1) structure, calculate the settlement tilt rate of the building (1) in different directions; Step 3: Based on the calculated settlement inclination rate of the building (1) in different directions, determine the main uplift area and the secondary uplift area, and take the axis corresponding to the direction with the minimum settlement inclination rate as the dividing line between the main uplift area and the secondary uplift area. Step 4: Grouting is performed under the raft slab (2) to form a shallow foundation protective layer (3) so that the bottom of the raft slab (2) is stress-coordinated; Step 5: Arrange multiple rows of spaced lifting holes diagonally on the surface of the raft plate (2), with the line connecting each row of lifting holes parallel to the boundary line between the main lifting area and the secondary lifting area. Step 6: Determine the orthographic projection of the lifting hole on the top of the building (1) as the lifting monitoring point, and record the instantaneous displacement of the area where the lifting hole is located during the lifting process; Step 7, grouting and tilt correction and lifting, includes: the grouting and lifting sequence starts from the position with the largest settlement in the main lifting area, and proceeds along the axis corresponding to the direction of the largest settlement inclination, until it reaches the position with the smallest settlement in the secondary lifting area; during grouting and lifting, the displacement changes of the lifting monitoring points are observed while grouting and lifting.

2. The grouting correction and lifting method for raft foundation structures as described in claim 1, characterized in that, In step two, the method for calculating the settlement inclination rate is as follows: For one of the axes along the origin, namely the north-south, east-west, northwest-southeast, and northeast-southwest axes, obtain the displacement difference between the settlement monitoring points at both ends of the building (1) on the axis, and divide the obtained displacement difference by the horizontal distance between the settlement monitoring points at both ends to obtain the settlement inclination rate in the direction of the axis.

3. The grouting correction and lifting method for raft foundation structures as described in claim 1, characterized in that, In step three, the settlement of the main uplift zone is greater than that of the secondary uplift zone.

4. The grouting correction and lifting method for raft foundation structures as described in claim 1, characterized in that, In step seven, during grouting and lifting, the first row of grouting holes is designated as J1, the second row as J2, and so on, with the nth row of grouting holes designated as Jn. First, grouting and lifting are performed on J1, and the lifting displacement of the area corresponding to J1 is observed at any time. Grouting is stopped when the horizontal height of the area corresponding to J1 is close to the horizontal height of the area corresponding to J2. Then, grouting is performed on J1 and J2 simultaneously, and the lifting changes of the areas corresponding to J1 and J2 are observed at any time. Grouting is stopped when the horizontal height of the areas corresponding to J1 and J2 is close to the horizontal height of the area corresponding to J3, and so on. Grouting is stopped when the horizontal height of the areas corresponding to J1, J2, ... J(n-1) is close to the horizontal height of the area corresponding to Jn. When the settlement tilt rate of the building (1) in each direction meets the requirements, the tilt correction and lifting work of the building (1) is completed.

5. The grouting correction and lifting method for raft foundation structures as described in claim 1, characterized in that, It also includes transmitting the displacement data of the monitoring points obtained by sensors deployed at settlement and uplift monitoring points to the monitoring system.

6. The grouting correction and lifting method for raft foundation structures as described in claim 1, characterized in that, The geological structure of the building (1) includes a backfill soil layer (4), a pebble layer (5), a foundation bearing layer (6), and a lift layer (7). The pebble layer (5) is located on the upper surface of the foundation bearing layer (6), and the backfill soil layer (4) is located on the upper surface of the pebble layer (5).

7. The grouting correction and lifting method for raft foundation structures as described in claim 6, characterized in that, The lower part of the lifting layer (7) is set in the foundation bearing layer (6), and the upper part is set in the pebble layer (5). A shallow foundation protection layer (3) is set on the upper surface of the lifting layer (7), and the shallow foundation protection layer (3) is set in the pebble layer (5). A raft slab (2) is set on the upper surface of the shallow foundation protection layer (3).

8. The grouting correction and lifting method for raft foundation structures as described in claim 7, characterized in that, The lower end face of the raft slab (2) is flush with the interface between the backfill soil layer (4) and the gravel layer (5), and a building (1) is set on the upper end face of the raft slab (2); the upper end face of the backfill soil layer (4) extends beyond the upper end face of the raft slab (2).

9. The grouting correction and lifting method for raft foundation structures as described in claim 8, characterized in that, The edge of the raised layer (7) is flush with the edge of the shallow foundation protective layer (3), the edge of the shallow foundation protective layer (3) extends beyond the edge of the raft slab (2), and the edge of the raft slab (2) extends beyond the edge of the building (1).

10. The grouting correction and lifting method for raft foundation structures as described in claim 9, characterized in that, In step seven, after the shallow foundation protective layer (3) reaches the design strength, grouting and lifting are carried out. The grouting pipe is inserted into the lifting hole and grouting and lifting are carried out below the shallow foundation protective layer (3) to construct a lifting layer (7) on the lower end face of the shallow foundation protective layer (3), thereby forming a supporting effect.

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