A method for staged settlement prevention and reinforcement of foundation

Abstract

The present invention provides a method for staged settlement prevention and reinforcement of foundation bases, which includes: when uneven settlement has occurred in a building, a plurality of first-stage settlement prevention piles are set on the settlement side, and a plurality of first-stage settlement control piles are set on the non-settlement side; the pile heads of each of the first-stage settlement prevention piles are respectively prestressed and sealed with load maintained, and the pile heads of each of the first-stage settlement control piles are not sealed; grouting pipes are arranged on the outer sides of the first-stage settlement control piles, and the required grouting materials are injected; a plurality of second-stage settlement prevention piles are set on the settlement side, and a plurality of second-stage settlement control piles are set on the non-settlement side; the pile heads of each of the first-stage settlement control piles, second-stage settlement control piles and second-stage settlement prevention piles are respectively prestressed and sealed with load maintained; grouting pipes are arranged on the outer sides of the second-stage settlement control piles, and the required grouting materials are respectively injected through the grouting pipes on the outer sides of the second-stage settlement control piles and the first-stage settlement control piles. Applying the present invention can effectively solve the problem of continuous increase in uneven settlement of existing buildings.

Description

Technical Field

[0001] This application relates to the technical field of building construction, and particularly relates to a method for staged settlement prevention and reinforcement of a foundation for controlling differential building settlement. Background Art

[0002] When an existing high-rise building has continuous uneven settlement and no tendency to converge, it is necessary to reinforce the foundation by adding piles. In the prior art, the commonly used reinforcement methods usually consider the final state of the settlement amount according to the design life and perform a one-time design.

[0003] However, in the prior art, for a building that is continuously settling, only the settlement amount in the final state after reinforcement is generally considered, and the settlement amount and settlement difference during the reinforcement process cannot be controlled and designed. Therefore, it is difficult to solve the problem of continuously increasing uneven settlement of existing buildings. Summary of the Invention

[0004] In view of this, the present invention provides a method for staged settlement prevention and reinforcement of a foundation, which can effectively solve the problem of continuously increasing uneven settlement of existing buildings.

[0005] The technical solution of the present invention is specifically implemented as follows:

[0006] A method for staged settlement prevention and reinforcement of a foundation, the method comprising:

[0007] When uneven settlement has occurred in the building, a plurality of first-stage settlement prevention piles are arranged on the settlement side of the building, and a plurality of first-stage settlement control piles are arranged on the non-settlement side of the building;

[0008] The pile heads of the respective first-stage settlement prevention piles on the settlement side are respectively subjected to prestressed load-holding pile capping, and the pile heads of the respective first-stage settlement control piles on the non-settlement side are not pile capped;

[0009] Grouting pipes are arranged outside the first-stage settlement control piles on the non-settlement side, and the required grouting materials are injected through the grouting pipes;

[0010] A plurality of second-stage settlement prevention piles are arranged on the settlement side of the building, and a plurality of second-stage settlement control piles are arranged on the non-settlement side of the building;

[0011] The pile heads of the respective first-stage settlement control piles, second-stage settlement control piles, and second-stage settlement prevention piles are respectively subjected to prestressed load-holding pile capping;

[0012] Grouting pipes are arranged outside the second-stage settlement control piles on the non-settlement side, and the required grouting materials are respectively injected through the grouting pipes outside the second-stage settlement control piles and the first-stage settlement control piles.

[0013] Furthermore, prestressed load-holding pile capping for the pile heads of each first-stage settlement-stopping pile on the settlement side includes:

[0014] Determine the settlement corresponding to each first-stage settlement-stopping pile according to the raft settlement and the specific positions of each first-stage settlement-stopping pile;

[0015] Determine the load corresponding to each first-stage settlement-stopping pile according to the static load test load-displacement curve in the area where the building is located and the settlement corresponding to each first-stage settlement-stopping pile;

[0016] Use the load corresponding to each first-stage settlement-stopping pile to perform prestressed immediate pile capping on each first-stage settlement-stopping pile.

[0017] Furthermore, when the original foundation of the building is a shallow foundation, the number of first-stage settlement-stopping piles is calculated according to the following formula:

[0018]

[0019] When the original foundation of the building is a pile foundation, the number of first-stage settlement-stopping piles is calculated according to the following formula:

[0020]

[0021] where n is the number of first-stage settlement-stopping piles, G k is the constant load corresponding to the settlement area, η c is the reduction coefficient of the bearing capacity of the foundation soil, f ak is the bearing capacity of the foundation soil, Q uk is the ultimate bearing capacity of the new pile, η R is the reduction coefficient of the bearing capacity of the original pile, R a0 is the bearing capacity of the original pile.

[0022] Furthermore, the number of first-stage settlement-control piles is calculated according to the following formula:

[0023] m = a * n

[0024] where m is the number of first-stage settlement-control piles, a is the reference coefficient, and the value range of a is 0.8 - 1.2.

[0025] Furthermore, when the original foundation of the building is a shallow foundation, the number of second-stage settlement-stopping piles is calculated according to the following formula:

[0026]

[0027] When the original foundation of the building is a pile foundation, the number of second-stage settlement-stopping piles is calculated according to the following formula:

[0028]

[0029] Wherein, N is the number of the second-stage settlement control piles, n is the number of the first-stage settlement control piles, F k is the vertical live load transmitted from the superstructure, G k is the corresponding dead load of the settlement area, η c is the reduction coefficient of the bearing capacity of the foundation soil, f ak is the bearing capacity of the foundation soil, η R1 is the reduction coefficient of the bearing capacity of the first-stage supplementary piles, R a1 is the characteristic value of the bearing capacity of the first-stage supplementary piles, R a2 is the characteristic value of the bearing capacity of the second-stage supplementary piles, η R is the reduction coefficient of the bearing capacity of the original piles, R a0 is the bearing capacity of the original piles.

[0030] Further, when the original foundation of the building is a shallow foundation, the number of the second-stage settlement control piles is calculated according to the following formula:

[0031]

[0032] When the original foundation of the building is a pile foundation, the number of the second-stage settlement control piles is calculated according to the following formula:

[0033]

[0034] Wherein, M is the number of the second-stage settlement control piles, and m is the number of the first-stage settlement control piles.

[0035] Further, the method further includes:

[0036] Calculating the subsequent total settlement and settlement difference of the building during its service life according to various current parameters of the building.

[0037] Further, the calculating the subsequent total settlement and settlement difference of the building during its service life according to various current parameters of the building includes:

[0038] Calculating the original settlement difference according to the superstructure information model, geological information and original pile parameters of the settlement side of the building;

[0039] Obtaining the measured value of the original settlement difference of the building, and calculating the settlement difference value according to the measured value of the original settlement difference and the original settlement difference;

[0040] When the settlement difference is 0, based on the original pile parameters on the non-settling side, the differential distribution information of geological parameters, the parameters of each first-stage settlement-stopping pile, first-stage settlement-controlling pile, second-stage settlement-stopping pile, and second-stage settlement-controlling pile, and the settlement difference, the subsequent total settlement amount and settlement difference of the building during its service life are calculated.

[0041] When the settlement difference is not 0, the original pile parameters on the settling side are adjusted, and the step of calculating the original settlement difference according to the upper structure information model, geological information, and original pile parameters on the settling side of the building is returned for execution.

[0042] As can be seen above, the foundation base staged settlement-stopping reinforcement method provided by the present invention can have the following beneficial effects:

[0043] (1) By using the foundation base staged settlement-stopping reinforcement method in the present invention, for high-rise buildings and super high-rise buildings, the problem of continuously increasing differential settlement can be effectively solved during the reinforcement construction stage.

[0044] (2) For high-rise buildings and super high-rise buildings, the problem of continuously increasing overall settlement and settlement difference of the building can also be effectively solved during the subsequent service stage.

[0045] (3) In the present invention, specific measures such as variable stiffness pile supplementing, differential pile sealing, first-stage grouting to reduce resistance and increase settlement, and second-stage grouting to increase resistance and reduce settlement are adopted for staged design, which can effectively level the inclination attitude of existing buildings. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 It is a schematic flow chart of the foundation base staged settlement-stopping reinforcement method in an embodiment of the present invention.

[0047] Figure 2 It is a schematic diagram of pile supplementing in the first stage in an embodiment of the present invention.

[0048] Figure 3 It is a schematic diagram of pile supplementing in the second stage in an embodiment of the present invention.

[0049] Figure 4 It is a schematic plan view of pile supplementing and reinforcement in the first stage in an embodiment of the present invention.

[0050] Figure 5 It is a schematic diagram of the Q-S curve in an embodiment of the present invention.

[0051] Figure 6 It is a schematic diagram of applying prestress to the pile top in an embodiment of the present invention.

[0052] Figure 7Schematic diagram of prestressed load-holding pile sealing in an embodiment of the present invention.

[0053] Figure 8 Schematic diagram of the first-stage post-grouting design for settlement control piles in an embodiment of the present invention.

[0054] Figure 9 For Figure 8 Schematic diagram of cross-section 1-1.

[0055] Figure 10 For Figure 8 Schematic diagram of cross-section 2-2.

[0056] Figure 11 Schematic plan view of supplementary pile reinforcement in the second stage in an embodiment of the present invention. Detailed implementation manners

[0057] To make the technical solutions and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0058] In the technical solution of the present invention, a method for staged settlement prevention and reinforcement of a foundation is proposed. This method is essentially a two-stage settlement prevention and reinforcement method, which can be divided into a first stage and a second stage. In the first stage, mainly based on the settlement difference and settlement rate of the existing building, settlement control and reinforcement design are carried out (for example, it can include immediate settlement prevention design on the side with large settlement and disturbance settlement control design on the side with small settlement) to control the existing settlement difference of the existing building, and at the same time level the inclination attitude of the existing building; in the second stage, mainly based on the bearing capacity and stiffness of the building foundation (pile foundation) and the bearing capacity and stiffness of the newly added piles, settlement prevention and reinforcement design are carried out to reduce the overall final settlement amount and settlement difference during the use of the existing building.

[0059] Figure 1 Schematic flow chart of the method for staged settlement prevention and reinforcement of a foundation in an embodiment of the present invention. As Figure 1 shown, in a specific embodiment of the present invention, the method for staged settlement prevention and reinforcement of a foundation includes:

[0060] Step 101, when uneven settlement occurs in the building, a plurality of first-stage settlement prevention piles are set on the settlement side of the building, and a plurality of first-stage settlement control piles are set on the non-settlement side of the building.

[0061] In the technical solution of the present invention, if uneven settlement (or differential settlement) has occurred in the existing building before reinforcement (for example, as Figure 2 shown, assuming that the settlement difference between the two ends of the foundation is △S, and the vertex displacement direction before reinforcement is Figure 2On the right side in, the inclination angle is Δδ, and the outer contour before settlement, the outer contour after settlement, and the raft settlement contour are as Figure 2 shown. Then, the first-stage settlement prevention reinforcement can be carried out first. In this stage, it is necessary to control the differential settlement from further developing within a short time, and at the same time, by taking different measures on the settlement side (or the side with large settlement) and the non-settlement side (the side with small settlement), the settlement difference can be further reduced or even eliminated, as Figure 2 shown.

[0062] To achieve the above purpose, a plurality of first-stage settlement prevention piles can be set on the settlement side (or the side with large settlement) of the building first, and a plurality of first-stage settlement control piles can be set on the non-settlement side (the side with small settlement) of the building.

[0063] For example, as an example, as Figure 4 shown, in a specific embodiment of the present invention, when differential settlement occurs on the south side of the building, a plurality of first-stage settlement prevention piles (for example, Figure 4 the B-1 pile and the B-2 pile shown in Figure 4 ) can be set on the settlement side of the building (for example, Figure 4 the south side in Figure 4 ), and a plurality of first-stage settlement control piles (for example,

[0064] the A-1 pile and the A-2 pile shown in

[0065] ) can be set on the non-settlement side of the building (for example,

[0066] the north side in

[0067]

[0068] In addition, in the technical solution of the present invention, the specific quantities of the above-mentioned first-stage settlement prevention piles and first-stage settlement control piles can be determined in advance according to the specific situation of the actual application scenario.

[0069]

[0070] Among them, n is the quantity of the first-stage settlement prevention piles, G k is the constant load corresponding to the settlement area, η c is the reduction coefficient of the bearing capacity of the foundation soil, f ak is the bearing capacity of the foundation soil, Q uk is the ultimate value of the bearing capacity of the newly added piles, η R is the reduction coefficient of the bearing capacity of the original piles, Ra0 is the bearing capacity of the original pile.

[0071] In the above formulas (1) and (2), only the actual dead load during construction can be considered, and the live load during the use period is not considered. The settlement area corresponds to the dead load G k , and the full play of the sinking prevention pile is fully considered.

[0072] Through the above formula (1) or formula (2), the number of the first-stage sinking prevention piles in different situations can be calculated.

[0073] In addition, in the technical solution of the present invention, according to the calculation results on the settlement side, a corresponding number of the first-stage settlement control piles can also be arranged on the non-settlement side (for example, Figure 4 the multiple A-1 piles and A-2 piles shown in

[0074] Since the settlement conditions of each building are different, and the building structures on the settlement side and the non-settlement side are not necessarily completely symmetrical, the number of the first-stage settlement control piles arranged on the non-settlement side (for example, Figure 4 the multiple A-1 piles and A-2 piles shown in Figure 4 is not necessarily exactly equal to the number of the first-stage sinking prevention piles arranged on the settlement side (for example,

[0075] the B-1 piles and B-2 piles shown in

[0076] m = a * n

[0077] where a is a reference coefficient, and the value range of a can be 0.8 to 1.2, that is, m = (0.8 to 1.2) * n.

[0078] Therefore, according to the above calculation results, n first-stage sinking prevention piles can be set on the settlement side of the building, and m first-stage settlement control piles can be set on the non-settlement side of the building.

[0079] In addition, after determining the number of the first-stage sinking prevention piles, the pile spacing between adjacent first-stage sinking prevention piles can be determined according to the plane area of the area to be prevented from sinking on the settlement side and the number of the first-stage sinking prevention piles, and then the specific positions of each first-stage sinking prevention pile can be determined.

[0080] Similarly, after determining the number of the first-stage settlement-control piles, the pile spacing between adjacent first-stage settlement-control piles can be determined according to the planar area of the area that needs to stop settlement on the non-settlement side and the number of the first-stage settlement-control piles, and then the specific positions of each first-stage settlement-control pile can be determined.

[0081] Step 102: Perform prestressed load-maintaining pile capping on the pile heads of each first-stage settlement-stopping pile on the settlement side, and do not perform pile capping on the pile heads of each first-stage settlement-control pile on the non-settlement side.

[0082] After setting the first-stage settlement-stopping piles and the first-stage settlement-control piles, a differential pile-capping operation needs to be carried out, which is mainly manifested in using different pile-capping forces and different pile-capping times for piles in different positions.

[0083] For example, in this step, for the pile heads of each first-stage settlement-stopping pile (i.e., the settlement-side pile heads), prestressed load-maintaining pile capping will be carried out; but for the pile heads of each first-stage settlement-control pile on the non-settlement side (i.e., the non-settlement-side pile heads), no pile capping will be carried out.

[0084] In addition, as an example, in a specific embodiment of the present invention, the performing of prestressed load-maintaining pile capping on the pile heads of each first-stage settlement-stopping pile on the settlement side may include:

[0085] Step 21: Determine the settlement amount corresponding to each first-stage settlement-stopping pile according to the raft settlement amount and the specific positions of each first-stage settlement-stopping pile.

[0086] For example, as Figure 4 shown, in a specific embodiment of the present invention, it is assumed that 5 first-stage settlement-stopping piles (which can be called B-1 piles) are set on the southernmost side of a building, and another 5 first-stage settlement-stopping piles (which can be called B-2 piles) are also set on the north side of the 5 B-1 piles; then, according to the raft settlement amount (as Figure 4 shown on the left) and the planar layout of each B-1 pile and B-2 pile, the settlement amount of each B-1 pile (which can be denoted as △S B-1 ) and the settlement amount of each B-2 pile (which can be denoted as △S B-2 ) can be determined.

[0087] Step 22: Determine the load corresponding to each first-stage settlement-stopping pile according to the static load test load-displacement (Q-S) curve of the area where the building is located and the settlement amount corresponding to each first-stage settlement-stopping pile.

[0088] For example, in a specific embodiment of the present invention, it is assumed that the static load test load-displacement (Q-S) curve of the area where the building is located is as Figure 5As shown, since the settlement amounts corresponding to the first-stage end-bearing piles have been determined in step 21, in this step, the loads corresponding to the first-stage end-bearing piles can be further determined according to the Q-S curve and the settlement amounts corresponding to the first-stage end-bearing piles.

[0089] For example, according to Figure 5 the Q-S curve shown, it can be determined that the load corresponding to the settlement amount △S of pile B-1 is △N B-1 , and the load corresponding to the settlement amount △S of pile B-2 is △N B-1 . B-2 , and the load corresponding to the settlement amount △S of pile B-2 is △N B-2 .

[0090] Step 23: Use the loads corresponding to the first-stage end-bearing piles to perform prestressed immediate pile sealing on the first-stage end-bearing piles.

[0091] In this step, after determining the loads corresponding to the first-stage end-bearing piles, the corresponding loads can be used to perform prestressed immediate pile sealing on the first-stage end-bearing piles.

[0092] For example, as an example, in a specific embodiment of the present invention, when the load corresponding to a certain pile B-1 is △N B-1 , prestressed immediate pile sealing can be performed on pile B-1 using a prestress of magnitude △N B-1 ; and when the load corresponding to a certain pile B-2 is △N B-2 , prestressed immediate pile sealing can be performed on pile B-2 using a prestress of magnitude △N B-2 ; and so on.

[0093] Therefore, through the above steps 21 to 23, prestressed load-holding pile sealing can be performed on the pile heads of the first-stage end-bearing piles on the settlement side.

[0094] In addition, as an example, as Figure 6 shown, in a specific embodiment of the present invention, the prestress can be applied to the pile top of the first-stage end-bearing pile by the following method:

[0095] A steel pipe force transfer cylinder is arranged at the pile top of the first-stage end-bearing pile, a jack is arranged at the top of the steel pipe force transfer cylinder, and a reaction beam is arranged at the top of the jack; the bottom of the force transfer cylinder of the jack abuts against the top of the steel pipe force transfer cylinder, and the top of the jack abuts against the bottom of the reaction beam;

[0096] Reaction anchor rods are arranged on both sides of the reaction beam; the top of the reaction anchor rod is fixedly connected to the reaction beam, and the bottom of the reaction anchor rod is implanted into the raft around the first-stage end-bearing pile;

[0097] Then, the required prestress can be applied to the pile top of the first-stage settlement-preventing pile through the above jack.

[0098] After applying the above prestress, concrete is poured into the pile core of the first-stage settlement-preventing pile, and the periphery of the steel pipe force transfer cylinder is also filled with concrete to form an enlarged head at the pile top of the first-stage settlement-preventing pile. The concrete is poured 10 - 15 cm below the raft board surface, leaving the recovery height of the steel bars on the board surface. After the concrete age reaches, the jack and the reaction beam are removed, the exposed force transfer cylinder and the reaction anchor bolts are cut off, the steel bars connecting the board surface are restored, and then the concrete is poured for the second time until the top surface of the raft board. As Figure 7 shown, thus completing the prestress holding and pile sealing of the pile head of the first-stage settlement-preventing pile.

[0099] Step 103, a grouting pipe is arranged on the outside of the first-stage settlement-controlling pile on the non-settlement side, and the required grouting material is injected through the grouting pipe.

[0100] In this step, the grouting pipe can be arranged on the outside of the first-stage settlement-controlling pile on the non-settlement side first.

[0101] For example, as an example, as Figures 8 - 10 shown, in a specific embodiment of the present invention, a grouting pipe can be arranged on the outside of the first-stage settlement-controlling pile, and the grouting pipe is fixedly connected to the first-stage settlement-controlling pile at the pile node (for example, the grouting pipe can be welded to the pile node of the first-stage settlement-controlling pile).

[0102] After arranging the above grouting pipe, the required grouting material can be injected through the grouting pipe to realize the post-grouting design of the first-stage settlement-controlling pile. The above grouting process will reduce the resistance and disturb the soil on the pile side, so that a certain additional settlement will occur on the non-settlement side.

[0103] In addition, as an example, in a specific embodiment of the present invention, the grouting pipe can be a galvanized steel pipe or a grouting pipe made of other suitable materials.

[0104] In addition, as an example, in a specific embodiment of the present invention, a lining steel casing can also be arranged at the pile connection node in the first-stage settlement-controlling pile, and the lining steel casing is sleeved inside the first-stage settlement-controlling pile, so as to play a strengthening role at the pile connection node.

[0105] In addition, in the technical solution of the present invention, the grouting material can adopt high-pressure water injection or AB component composite grouting material (in the first stage, only the A component material can be injected, which is a liquid grouting material with relatively high fluidity, and the single A component cannot consolidate the soil).

[0106] Step 104: Set multiple second-stage settlement prevention piles on the settlement side of the building and set multiple second-stage settlement control piles on the non-settlement side of the building.

[0107] In the technical solution of the present invention, the above steps 101-103 can be used as the first stage (partial settlement control stage) of the foundation sub-stage settlement prevention and reinforcement method in the present invention.

[0108] After controlling the settlement difference that has occurred in the building through the first stage, the second stage (settlement prevention stage) of the foundation sub-stage settlement prevention and reinforcement method in the present invention can be carried out according to the differential settlement control result of the building after the first stage of reinforcement, so as to control the subsequent overall settlement amount and settlement difference of the building within the service life (for example, as Figure 3 shown, assuming that the settlement difference of the foundation at both ends of the foundation is △S, the side shift direction of the apex after reinforcement is Figure 3 to the left in Figure 3 and the inclination angle is Δδ′, the outer contour before reinforcement and the outer contour after reinforcement are as

[0109] shown).

[0110] For example, as an example, as Figure 11 shown, in a specific embodiment of the present invention, multiple second-stage settlement prevention piles (for example, Figure 11 the D-2 pile shown in Figure 11 ) can be set on the settlement side of the building (for example, Figure 11 the south side in Figure 11 ), and multiple second-stage settlement control piles (for example,

[0111] the C-2 pile shown in

[0112] ) can be set on the non-settlement side of the building (for example,

[0113] the north side in

[0114] ). Among them, the second-stage settlement prevention piles are generally set inside the first-stage settlement prevention piles, closer to the middle of the building; and the second-stage settlement control piles are also generally set inside the first-stage settlement control piles, closer to the middle of the building. In addition, in the technical solution of the present invention, the specific quantities of the above second-stage settlement prevention piles and second-stage settlement control piles can be determined in advance according to the specific situation of the actual application scenario.

[0112] For example, as an example, in a specific embodiment of the present invention, the quantity of the second-stage settlement prevention piles can be determined according to the following method:

[0113] When the original foundation of the building is a shallow foundation, the quantity of the second-stage settlement prevention piles is calculated according to the following formula:

[0114]

[0115] When the original foundation of the building is a pile foundation, the number of the second-stage settlement-stop piles is calculated according to the following formula:

[0116]

[0117] Wherein, N is the number of the second-stage settlement-stop piles, n is the number of the first-stage settlement-stop piles, F k is the vertical live load transmitted from the superstructure, G k is the dead load corresponding to the settlement area, η c is the reduction coefficient of the bearing capacity of the foundation soil, f ak is the bearing capacity of the foundation soil, η R1 is the reduction coefficient of the bearing capacity of the first-stage supplementary piles, R a1 is the characteristic value of the bearing capacity of the first-stage supplementary piles, R a2 is the characteristic value of the bearing capacity of the second-stage supplementary piles, η R is the reduction coefficient of the bearing capacity of the original piles, R a0 is the bearing capacity of the original piles.

[0118] Through the above formula (3) or formula (4), the number of the second-stage settlement-stop piles in different cases can be calculated.

[0119] In addition, in the technical solution of the present invention, the number M of the second-stage settlement-control piles (for example, the C-2 pile shown in Figure 11 ) can also be determined according to the following method:

[0120] When the original foundation of the building is a shallow foundation, the number of the second-stage settlement-control piles is calculated according to the following formula:

[0121]

[0122] When the original foundation of the building is a pile foundation, the number of the second-stage settlement-control piles is calculated according to the following formula:

[0123]

[0124] Wherein, M is the number of the second-stage settlement-control piles, and m is the number of the first-stage settlement-control piles.

[0125] Therefore, according to the above calculation results, N second-stage settlement-stop piles can be set on the settlement side of the building, and M second-stage settlement-control piles can be set on the non-settlement side of the building.

[0126] In addition, after determining the number of the second-stage sinking prevention piles, the pile spacing between adjacent second-stage sinking prevention piles can be determined according to the planar area of the area to be reinforced on the settlement side and the number of the second-stage sinking prevention piles, and then the specific positions of each second-stage sinking prevention pile can be determined.

[0127] Similarly, after determining the number of the second-stage settlement control piles, the pile spacing between adjacent second-stage settlement control piles can be determined according to the planar area of the area to be reinforced on the non-settlement side and the number of the second-stage settlement control piles, and then the specific positions of each second-stage settlement control pile can be determined.

[0128] In addition, in the technical solution of the present invention, since the second-stage sinking prevention piles and the second-stage settlement control piles are generally arranged in the middle of the building, the pile length or pile diameter of the second-stage sinking prevention piles and the second-stage settlement control piles can be appropriately reduced so that it is smaller than the pile length or pile diameter of the first-stage sinking prevention piles and the first-stage settlement control piles.

[0129] Step 105: Perform prestressed load-holding pile capping on the pile heads of each first-stage settlement control pile, second-stage settlement control pile, and second-stage sinking prevention pile respectively.

[0130] After setting the second-stage settlement control piles and the second-stage sinking prevention piles, differential pile capping operations also need to be carried out.

[0131] For example, in this step, prestressed load-holding pile capping will be carried out on the pile heads of each first-stage settlement control pile, second-stage settlement control pile, and second-stage sinking prevention pile respectively.

[0132] In addition, as an example, in a specific embodiment of the present invention, when performing prestressed load-holding pile capping in this step, the specific implementation method can refer to the specific implementation method of performing prestressed load-holding pile capping on the pile heads of each first-stage sinking prevention pile on the settlement side in step 102, which will not be elaborated here.

[0133] In addition, as an example, in a specific embodiment of the present invention, the pile heads of each second-stage sinking prevention pile (for example, the D-2 pile shown in Figure 11 ) can be respectively subjected to prestressed load-holding pile capping first, and then the pile heads of each first-stage settlement control pile (for example, the A-1 pile and A-2 pile shown in Figure 11 ) can be respectively subjected to prestressed load-holding pile capping, and finally the pile heads of each second-stage settlement control pile (for example, the C-2 pile shown in Figure 11 ) can be respectively subjected to prestressed load-holding pile capping. A preset time interval can be set between each batch of prestressed load-holding pile capping, so as to meet the differences in the pile capping timing according to the actual application scenario (for example, the on-site settlement situation).

[0134] Step 106: Set up grouting pipes outside the second-stage settlement control piles on the non-settling side, and inject the required grouting materials through the grouting pipes outside the second-stage settlement control piles and the first-stage settlement control piles respectively.

[0135] In this step, the grouting pipes can be set up outside the second-stage settlement control piles on the non-settling side first. The specific implementation method of the grouting pipes can refer to the specific implementation method in Step 103, which will not be elaborated here.

[0136] After setting up the above grouting pipes, the required grouting materials can be injected through the grouting pipes outside the second-stage settlement control piles and the first-stage settlement control piles respectively to realize the post-grouting design of the second-stage settlement control piles and the first-stage settlement control piles.

[0137] In addition, as an example, in a specific embodiment of the present invention, the required grouting materials can be injected through the grouting pipes of the second-stage settlement control piles first, and then the required grouting materials can be injected through the grouting pipes outside the first-stage settlement control piles, so as to solidify the soil body, increase the side resistance and end resistance, and improve the bearing capacity of the foundation piles.

[0138] In addition, as an example, in a specific embodiment of the present invention, the grouting material can be a quick-setting geotechnical grouting material or other suitable grouting materials.

[0139] In addition, as an example, in a specific embodiment of the present invention, if component A has been injected through the grouting pipes outside the first-stage settlement control piles in the first stage, it can be determined whether it is necessary to inject component B through the grouting pipes outside the first-stage settlement control piles according to the actual application scenario, so as to combine with the previously injected component A to solidify the soil body.

[0140] Through the above steps 101 to 106, the settlement prevention and reinforcement of the building with settlement can be carried out in stages.

[0141] In addition, as an example, in a specific embodiment of the present invention, the above-mentioned staged settlement prevention and reinforcement method for the foundation can further include:

[0142] Step 107: Calculate the subsequent total settlement amount and settlement difference of the building during its service life according to various current parameters of the building.

[0143] After setting the first-stage settlement prevention piles, the first-stage settlement control piles, the second-stage settlement prevention piles and the second-stage settlement control piles for the building in two stages respectively, the settlement prevention and reinforcement of the building with settlement can be effectively carried out. At this time, it can be further calculated according to various current parameters of the building to obtain the subsequent total settlement amount and settlement difference of the building during its service life.

[0144] In the technical solution of the present invention, the above step 107 can be implemented through various specific implementation manners. Hereinafter, taking one of the specific implementation manners as an example, the technical solution of the present invention will be introduced in detail.

[0145] For example, as an example, in a specific embodiment of the present invention, the step 107 may include the following steps:

[0146] Step 71, calculate the original settlement difference according to the upper structure information model of the building, the geological information, and the original pile parameters on the settlement side.

[0147] In this step, relevant information of the building can be obtained first, such as the upper structure information model, the geological information, and the original pile parameters on the settlement side, etc., and then the corresponding original settlement difference (i.e., the theoretical value of the settlement difference before the staged settlement stopping and reinforcement) can be calculated according to these information.

[0148] Step 72, obtain the measured value of the original settlement difference of the building, and calculate the settlement difference value according to the measured value of the original settlement difference and the original settlement difference.

[0149] After calculating the original settlement difference, the original settlement difference can be compared with the measured value of the original settlement difference of the building obtained on site (i.e., the measured value of the settlement difference before the staged settlement stopping and reinforcement), and the corresponding settlement difference value can be calculated, so as to check the accuracy of the original pile parameters on the settlement side, so as to adjust the original pile parameters on the settlement side in the subsequent steps, and perform the comparison calculation again until the difference between the two is 0.

[0150] Step 73, when the settlement difference value is not 0, adjust the original pile parameters on the settlement side, and return to execute step 71; when the settlement difference value is 0, execute step 74.

[0151] In this step, first judge whether the settlement difference value calculated in step 72 is 0. When the settlement difference value is not 0, it means that the original pile parameters on the settlement side are not accurate enough, so the original pile parameters on the settlement side will be adjusted accordingly, and then return to execute steps 71 and 72, perform the comparison calculation again, obtain a new settlement difference value, and then execute step 73. When the settlement difference value is 0, it means that the original pile parameters on the settlement side are already relatively accurate, and at this time, the subsequent step 74 can be executed.

[0152] Step 74, calculate the subsequent overall settlement amount and settlement difference of the building during its service life according to the original pile parameters on the non-settlement side, the differential distribution information of the geological parameters, the parameters of each first-stage settlement-stopping pile, the first-stage settlement-control pile, the second-stage settlement-stopping pile, and the second-stage settlement-control pile, and the settlement difference value.

[0153] In this step, the original pile parameters on the non-settling side, the differential distribution information of geological parameters, and the parameters of each first-stage settlement-stopping pile, first-stage settlement-controlling pile, second-stage settlement-stopping pile, and second-stage settlement-controlling pile can be obtained first. Then, calculations are carried out again based on the obtained parameters and the settlement difference calculated above, and finally the subsequent overall settlement amount and settlement difference of the building during its service life are obtained.

[0154] Therefore, through the above steps 71 to 74, the subsequent overall settlement amount and settlement difference of the building during its service life can be calculated based on various current parameters of the building.

[0155] In summary, the foundation base staged settlement-stopping reinforcement method provided in the present invention can have the following beneficial technical effects:

[0156] (1) By using the foundation base staged settlement-stopping reinforcement method in the present invention, for high-rise buildings and super high-rise buildings, the problem of continuously increasing differential settlement can be effectively solved during the reinforcement construction stage.

[0157] (2) For high-rise buildings and super high-rise buildings, the problem of continuously increasing overall settlement and settlement difference of the building can also be effectively solved during the subsequent use stage.

[0158] (3) In the present invention, specific measures such as variable stiffness pile supplementing, differential pile sealing, first-stage grouting to reduce resistance and increase settlement, and second-stage grouting to increase resistance and reduce settlement are adopted for staged design, which can effectively level the inclination attitude of the existing building.

[0159] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A method for stagewise settlement prevention and reinforcement of a foundation, characterized in that, The method includes: When uneven settlement has occurred in the building, a plurality of first-stage settlement prevention piles are set on the settlement side of the building, and a plurality of first-stage settlement control piles are set on the non-settlement side of the building; The pile heads of the respective first-stage settlement prevention piles on the settlement side are respectively prestressed and load-held for pile sealing, and the pile heads of the respective first-stage settlement control piles on the non-settlement side are not pile-sealed; Grouting pipes are arranged on the outer sides of the first-stage settlement control piles on the non-settlement side, and the required grouting materials are injected through the grouting pipes; A plurality of second-stage settlement prevention piles are set on the settlement side of the building, and a plurality of second-stage settlement control piles are set on the non-settlement side of the building; The pile heads of the respective first-stage settlement control piles, second-stage settlement control piles, and second-stage settlement prevention piles are respectively prestressed and load-held for pile sealing; Grouting pipes are arranged on the outer sides of the second-stage settlement control piles on the non-settlement side, and the required grouting materials are respectively injected through the grouting pipes on the outer sides of the second-stage settlement control piles and the first-stage settlement control piles; The prestressing and load-holding pile sealing of the pile heads of the respective first-stage settlement prevention piles on the settlement side respectively includes: Based on the raft settlement amount and the specific positions of the respective first-stage settlement prevention piles, determining the settlement amounts corresponding to the respective first-stage settlement prevention piles; Based on the static load test load-displacement curve in the area where the building is located and the settlement amounts corresponding to the respective first-stage settlement prevention piles, determining the loads corresponding to the respective first-stage settlement prevention piles; Using the loads corresponding to the respective first-stage settlement prevention piles to perform prestressed immediate pile sealing on the respective first-stage settlement prevention piles; When the original foundation of the building is a shallow foundation, the number of first-stage settlement prevention piles is calculated according to the following formula: When the original foundation of the building is a pile foundation, the number of first-stage settlement prevention piles is calculated according to the following formula: Wherein, n is the number of the end-bearing piles in the first stage, G k is the constant load corresponding to the settlement area, η c is the reduction coefficient of the bearing capacity of the foundation soil, f ak is the bearing capacity of the foundation soil, Q uk is the ultimate value of the bearing capacity of the new piles, η R is the reduction coefficient of the bearing capacity of the original piles, R a0 is the bearing capacity of the original piles.

2. The method for stage-by-stage settlement prevention and reinforcement of foundation bases according to claim 1, characterized in that, The number of first-stage settlement control piles is calculated according to the following formula: m = a * n Wherein, m is the number of first-stage settlement control piles, a is a reference coefficient, and the value range of a is 0.8 to 1.

2.

3. The method for staged settlement prevention and reinforcement of the foundation according to claim 2, wherein When the original foundation of the building is a shallow foundation, the number of second-stage settlement prevention piles is calculated according to the following formula: When the original foundation of the building is a pile foundation, the number of second-stage settlement prevention piles is calculated according to the following formula: Wherein, N is the number of the sinking-stop piles in the second stage, n is the number of the sinking-stop piles in the first stage, F k is the vertical live load transmitted from the superstructure, G k is the dead load corresponding to the settlement area, η c is the reduction coefficient of the bearing capacity of the foundation soil, f ak is the bearing capacity of the foundation soil, η R1 is the reduction coefficient of the bearing capacity of the supplementary piles in the first stage, R a1 is the characteristic value of the bearing capacity of the supplementary piles in the first stage, R a2 is the characteristic value of the bearing capacity of the supplementary piles in the second stage, η R is the reduction coefficient of the bearing capacity of the original piles, R a0 is the bearing capacity of the original piles.

4. The method for staged settlement prevention and reinforcement of the foundation according to claim 3, wherein When the original foundation of the building is a shallow foundation, the number of second-stage settlement control piles is calculated according to the following formula: When the original foundation of the building is a pile foundation, the number of second-stage settlement control piles is calculated according to the following formula: Wherein, M is the number of second-stage settlement control piles, and m is the number of first-stage settlement control piles.

5. The method for staged settlement prevention and reinforcement of foundation bases according to claim 1, characterized in that, The method further includes: Calculating the subsequent total settlement amount and settlement difference of the building during its service life according to various current parameters of the building.

6. The method for staged settlement prevention and reinforcement of foundation bases according to claim 5, characterized in that, The calculating the subsequent total settlement amount and settlement difference of the building during its service life according to various current parameters of the building includes: Calculating the original settlement difference based on the upper structure information model, geological information, and original pile parameters on the settlement side of the building; Obtain the measured value of the original settlement difference of the building, and calculate the settlement difference value based on the measured value of the original settlement difference and the original settlement difference; When the settlement difference value is 0, calculate the subsequent overall settlement amount and settlement difference of the building during its service life according to the original pile parameters on the non-settlement side, the differential distribution information of geological parameters, the parameters of each first-stage settlement-stopping pile, first-stage settlement-controlling pile, second-stage settlement-stopping pile, and second-stage settlement-controlling pile, and the settlement difference value; When the settlement difference value is not 0, adjust the original pile parameters on the settlement side, and return to execute the step of calculating the original settlement difference according to the upper structure information model of the building, the geological information, and the original pile parameters on the settlement side.

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