Local grouting method construction technology

Abstract

The invention relates to the technical field of pile foundation construction, and discloses a local grouting method construction process, which is applied to unknown cause stratums or lava development stratums, and comprises the following steps of: determining a positioning hole at the central position of a grouting hole by using a theodolite according to existing coordinate control points of a project, a geological survey report and construction survey data; the hole positions of the grouting holes are determined according to the positioning holes; percussion drilling is adopted according to the hole position of the grouting hole, a soil core is taken in the whole hole, and drilling is stopped until a hard layer is touched; after the grouting hole is formed, a steel sleeve is put down to remove mud and sediment in the hole; a steel sleeve is arranged downwards, grouting equipment is adopted to inject and configure grout into preset positions in the grouting holes, and grouting is ended after the grouting end standard is met within the grouting depth range till grouting of all the grouting holes is completed; and after grouting is completed, grouting holes are backfilled after grout is solidified. The problems that the construction period is long and the construction difficulty is large in an existing unknown formation cause stratum or karst development stratum treatment construction technology are solved.

Description

Technical Field

[0001] This invention relates to the field of pile foundation construction technology, and specifically to a local grouting construction process. Background Technology

[0002] In the construction process of treating strata of unknown origin or karst development, the traditional approach is to use the backfilling method. Generally, the engineering piles to be constructed are first drilled, and after rotary excavation to the stratum to be treated, crushed stone, gravel, concrete or other suitable materials are filled into the karst cave. However, this construction process has a long construction period and is difficult to carry out. Summary of the Invention

[0003] In view of this, the present invention provides a local grouting construction process to solve the problems of long construction period and high construction difficulty in the existing construction process for treating strata of unknown origin or karst development.

[0004] This invention provides a local grouting construction process applicable to strata of unknown origin or strata with developed lava, comprising the following steps:

[0005] Measurement of borehole location: Based on the existing coordinate control points of the project, geological survey report and construction survey data, the center position of the grouting hole is determined by the theodolite, and the hole position of the grouting hole is determined based on the positioning hole;

[0006] Drilling: Percussion drilling is used according to the location of the grouting holes, and soil cores are taken from the entire hole until a hard layer is reached and then drilling is stopped;

[0007] Hole cleaning: After the grouting hole is formed, a steel casing is installed to remove the mud and sediment from the hole;

[0008] Grouting: A steel sleeve is placed at the bottom, and the prepared grout is injected into the pre-set position in the grouting hole using grouting equipment. Grouting is stopped after the grouting end standard is met within the grouting depth range, until all grouting holes are grouted.

[0009] After grouting is completed, wait for the grout to solidify and then backfill the grouting holes.

[0010] In one optional implementation, the step of determining the positioning hole, which uses a theodolite to locate the center position of the grouting hole based on existing coordinate control points, geological survey reports, and construction survey data, and then determining the hole position of the grouting hole based on the positioning hole, specifically includes the following steps:

[0011] The positioning hole, located at the center of the grouting hole, was determined using a theodolite based on the existing coordinate control points, geological survey report, and construction survey data.

[0012] Centered on the positioning hole, the number and diameter of the grouting holes are determined according to the diameter of the foundation pile; the multiple grouting holes are evenly arranged around the positioning hole on the outer ring of the foundation pile, and the multiple grouting holes are interlocked with each other.

[0013] In one optional embodiment, the lower steel sleeve is injected with the prepared grout at a predetermined position in the grouting hole using grouting equipment. Grouting is stopped after the grouting end standard is met within the grouting depth range, until the grouting of all grouting holes is completed. This specifically includes the following steps:

[0014] A lower steel casing is installed, the top of which is sealed to the grout delivery hose of the grouting equipment, and at least one of sand or gravel is poured in to form a filler.

[0015] Grouting is performed using a grouting pipe, which is inserted to the bottom of the filler. The grouting equipment injects grout into the grouting hole through the grouting pipe in an intermittent grouting manner within a preset pressure range. Each grouting is performed after the grout from the previous grouting has initially bonded with the filler. During grouting, the grouting pipe is slowly lifted at a preset lifting speed while grouting at a preset grouting speed, and the grouting is repeated multiple times.

[0016] Grouting is stopped once the grouting end criteria are met within the grouting depth range. After grouting one hole, grouting continues for other holes, and the pressure of subsequent grouting is increased. After all grouting holes are completed, the holes are sealed.

[0017] In one alternative embodiment, the grouting pipe is a single-flower pipe.

[0018] In one optional embodiment, the preset pressure range is 0.5MPa to 1.0MPa.

[0019] In one optional embodiment, the preset grouting speed is 15L / min to 20L / min.

[0020] In one alternative embodiment, the slurry comprises cement slurry and water glass.

[0021] In one alternative embodiment, the slurry comprises cement mortar and water glass.

[0022] In one optional embodiment, the grouting depth ranges from 3m to 4m from the bottom of strata of unknown origin or strata with lava development.

[0023] In one optional embodiment, the grouting termination criterion is when the grouting volume is less than 20 L / min, the grouting pressure reaches 0.5 to 1.0 MPa, and this pressure is maintained for 10 minutes.

[0024] Alternatively, the grouting termination criterion is when the grouting pressure reaches 1.0–1.5 MPa and the grout is difficult to inject;

[0025] Alternatively, the grouting termination criterion is when the grouting volume in a single hole reaches more than 1.5 times the average grouting volume, and the grouting volume decreases significantly;

[0026] Alternatively, the grouting completion criterion is if grouting reaches 30m. 3 If no pressure rise occurs, stop grouting and wait for the grout to harden before continuing grouting. Repeat this process until the grouting reaches the preset depth.

[0027] The technical solution of this invention has the following advantages:

[0028] This invention uses a theodolite to determine the center position of the grouting holes based on existing coordinate control points, geological survey reports, and construction survey data. These positioning holes mark the installation locations of the foundation piles, facilitating the determination of the grouting hole positions on the outer periphery of the piles according to their diameter. The number of positioning holes is selected based on actual needs, i.e., the number of foundation piles required; one or more holes can be used. By clearly defining the grouting hole positions through these positioning holes, the number of holes can be reduced, shortening the construction period. Then, based on the grouting hole positions, percussion drilling is employed to obtain soil cores from the entire hole. If karst caves or fluid-filled materials are present, it is identified as a "drill failure," requiring continued drilling until... Drilling stops upon reaching a hard layer. Next, a steel pipe is inserted into the grouting hole to support the sidewall, facilitating the removal of mud and sediment for grouting and ensuring grouting effectiveness. Another steel casing is lowered to protect the sidewall of the grouting hole. Then, the prepared grout is injected into a pre-set position within the grouting hole using grouting equipment. Grouting is stopped once the grouting depth meets the grouting completion criteria, until all grouting holes are grouted. While ensuring structural strength, the grouting depth is strictly controlled to achieve localized grouting, avoiding grout waste, reducing costs and construction difficulty, simplifying the construction process, and improving construction efficiency. Finally, after grouting is completed, the grout is allowed to solidify and then backfilled into the grouting hole. Attached Figure Description

[0029] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0030] Figure 1 This is a flowchart of a local grouting construction process according to an embodiment of the present invention;

[0031] Figure 2 This is a schematic diagram of the grouting cross-section of the local grouting construction process according to an embodiment of the present invention;

[0032] Figure 3 This is a diagram showing the arrangement of grouting holes for a single pile according to an embodiment of the present invention.

[0033] Figure 4 This is a diagram showing the arrangement of grouting holes in the three-pile cap according to an embodiment of the present invention.

[0034] Explanation of reference numerals in the attached figures:

[0035] 1. Positioning hole; 2. Grouting hole; 3. Grouting pipe; 4. Plain fill layer; 5. Silty clay layer; 6. Strongly weathered argillaceous siltstone layer; 7. Slightly weathered limestone layer; 8. Dual grouting fluid. Detailed Implementation

[0036] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0037] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0038] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0039] Furthermore, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0040] The following is combined with Figures 1 to 4 The following describes embodiments of the present invention.

[0041] According to embodiments of the present invention, such as Figure 1As shown, a local grouting construction technique is provided, applicable to strata of unknown origin or strata with developed lava, including the following steps:

[0042] Step S1: Measure the location of the drilling hole: Based on the existing coordinate control points of the project, the geological survey report and the construction survey data, use a theodolite to determine the positioning hole 1 at the center of the grouting hole 2, and determine the hole position of the grouting hole 2 based on the positioning hole 1.

[0043] It should be noted that the positioning hole 1 is used for positioning and installing the foundation pile.

[0044] In this embodiment of the invention, a positioning hole 1 is used to determine the center position of the grouting hole 2 based on the existing coordinate control points, geological survey report, and construction survey data of the project using a theodolite. The positioning hole 1 is the installation position of the foundation pile, so that the hole position of the grouting hole 2 can be determined on the outer periphery of the foundation pile according to the diameter of the foundation pile to be installed. The number of positioning holes 1 is selected according to actual needs, that is, the number of foundation piles to be set can be selected as needed, which can be one or multiple. By clarifying the hole position of the grouting hole 2 through the positioning hole 1, the hole position arrangement of the grouting hole 2 is reduced and the construction period is shortened.

[0045] Step S2, Drilling: According to the position of grouting hole 2, use impact drilling to extract soil cores from the entire hole until a hard layer is reached and then stop drilling;

[0046] In this embodiment of the invention, percussion drilling is used according to the position of the grouting hole 2, and soil cores are taken from the whole hole. When there is a karst cave or fluid filling material, it is identified as "drill drop", and drilling needs to continue until a hard layer is reached and then drilling stops.

[0047] Step S3, Hole Cleaning: After the grouting hole 2 is formed, a steel casing is installed to remove the mud and sediment from the hole;

[0048] In this embodiment of the invention, the sidewall is supported by a lower steel pipe sleeve inside the grouting hole 2, which facilitates the grouting of mud and sediment inside the grouting hole 2 and ensures the grouting effect.

[0049] Step S4, Grouting: Place the steel sleeve and use grouting equipment to inject the prepared grout at the pre-set position in the grouting hole 2. After the grouting depth meets the grouting end standard, the grouting is stopped until all grouting holes 2 are grouted.

[0050] In this embodiment of the invention, the sidewall of the grouting hole 2 is protected by a lower steel sleeve. Then, the prepared grout is injected into the grouting hole 2 at a predetermined position using grouting equipment. Grouting is stopped after the grouting end standard is met within the grouting depth range until all grouting holes 2 are grouted. While ensuring structural strength, the grouting depth is strictly controlled to achieve local grouting, avoid grout waste, reduce costs and construction difficulty, simplify the construction process, and thus improve construction efficiency.

[0051] Step S5: After grouting is completed, wait for the grout to solidify and then backfill the grouting hole 2.

[0052] In this embodiment of the invention, after grouting is completed, the grout is allowed to solidify to ensure structural strength. Preferably, the waiting time is 7 hours. The grouting hole 2 is then backfilled to facilitate the installation of the foundation pile.

[0053] In this embodiment of the invention, firstly, based on the existing coordinate control points, geological survey report, and construction survey data, a theodolite is used to determine the positioning hole 1 at the center of the grouting hole 2. This positioning hole 1 is the installation position of the foundation pile, so that the hole position of the grouting hole 2 can be determined on the outer periphery of the foundation pile according to the diameter of the foundation pile to be installed. The number of positioning holes 1 is selected according to actual needs, that is, the number of foundation piles to be set can be selected as needed, which can be one or multiple. By clarifying the hole position of the grouting hole 2 through the positioning hole 1, the number of hole positions of the grouting hole 2 is reduced, and the construction period is shortened. Then, according to the hole position of the grouting hole 2, impact drilling is used to obtain soil cores from the whole hole. When there are karst caves or fluid filling materials, it is identified as "drill drop", and then it is necessary to continue. Drilling continues until a hard layer is reached, at which point drilling stops. Next, a steel casing is inserted into the grouting hole 2 to support the sidewall, facilitating the removal of mud and sediment within the hole and ensuring grouting effectiveness. Another steel casing is then lowered to protect the sidewall of the grouting hole 2. Next, the prepared grout is injected into the pre-set position within the grouting hole 2 using grouting equipment. Grouting is stopped once the grouting depth meets the grouting completion standard, until all grouting holes 2 are grouted. While ensuring structural strength, the grouting depth is strictly controlled to achieve localized grouting, avoiding grout waste, reducing costs and construction difficulty, simplifying the construction process, and thus improving construction efficiency. Finally, after grouting is completed, the grout is allowed to solidify and then backfilled into the grouting hole 2.

[0054] In one embodiment, step S1 specifically includes the following steps:

[0055] Step S101: Based on the existing coordinate control points, geological survey report and construction survey data of the project, use a theodolite to determine the positioning hole 1 at the center position of the grouting hole 2;

[0056] It should be noted that, based on the geological conditions of the advanced drilling reaction, the grouting holes 2 are evenly arranged with the pile hole wall of the rotary drilling foundation pile as the center, and the grout penetration radius is pre-controlled at 0.3m.

[0057] In this embodiment of the invention, the positioning hole 1, which is the center position of the grouting hole 2, is determined by a theodolite based on the existing coordinate control points, geological survey report and construction survey data. The positioning hole 1 is the installation position of the foundation pile, so that the hole position of the grouting hole 2 can be determined on the outer periphery of the foundation pile according to the diameter of the foundation pile, which is convenient and quick and reduces the difficulty of construction.

[0058] Step S102: Taking the positioning hole 1 as the center, determine the number and diameter of the grouting holes 2 according to the diameter of the foundation pile; wherein, the positions of the multiple grouting holes 2 are evenly arranged around the positioning hole 1 on the outer ring of the foundation pile, and the multiple grouting holes 2 are interlocked with each other.

[0059] It should be noted that, as Figure 3 and Figure 4 As shown, the arrangement principle of the grouting holes 2 is: the center point of the grouting holes 2 is on the outer periphery of the foundation pile, and multiple grouting holes 2 interlock with each other.

[0060] In this embodiment of the invention, the number and diameter of the grouting holes 2 are determined according to the position of the positioning hole 1 and the diameter of the foundation pile, ensuring that multiple grouting holes 2 are interlocked and arranged so that the grout can penetrate and cover the surrounding area of ​​the foundation pile during grouting, thus ensuring structural strength. The number of foundation piles can be one or more. The positioning hole 1 clarifies the position of the grouting holes 2, and the interlocking arrangement of multiple grouting holes 2 meets the structural strength requirements after grouting, reducing the number of grouting hole positions and shortening the construction period. Preferably, when the diameter of the foundation pile is 1m, there are 3 grouting holes 2, and the diffusion radius of the grouting holes 2 is 600mm. Other foundation piles follow the same principle, which will not be elaborated here.

[0061] In one embodiment, such as Figure 3 As shown, one foundation pile is installed.

[0062] In one embodiment, such as Figure 4 As shown, three foundation piles are installed.

[0063] In one embodiment, step S4 specifically includes the following steps:

[0064] Step S401: Lower the steel casing, and seal the top of the steel casing to the grout delivery hose of the grouting equipment, and fill it with at least one of sand or gravel to form a filler.

[0065] In this embodiment of the invention, the structural strength after grouting solidification is improved by injecting filler.

[0066] Step S402: Grouting is performed using grouting pipe 3. The grouting pipe 3 is inserted to the bottom of the filler. The grouting equipment injects grout into the grouting hole 2 through the grouting pipe 3 in an intermittent grouting manner within the preset pressure range. Each grouting is performed after the grout from the previous grouting has initially bonded with the filler. During grouting, the grouting pipe 3 is slowly lifted at the preset lifting speed while grouting at the preset grouting speed. The grouting is repeated multiple times.

[0067] It should be noted that supplementary grouting should be carried out in areas with poor grouting effect. That is, the grouting speed and grouting pressure should be within the preset grouting range. If they do not meet the requirements, supplementary grouting should be carried out until the requirements are met. During the grouting process, ground observation should be strengthened and records should be kept. When the ground rise and fall reaches 10 mm / d and the horizontal displacement exceeds 5 mm / d, grouting should be suspended near existing lines and existing buildings. Special circumstances should be reported to relevant departments for handling in a timely manner.

[0068] In the embodiment of the invention, intermittent grouting is adopted. Grout is injected through grouting pipe 3 within a preset pressure range to avoid excessive grouting pressure damaging the side wall structure of grouting hole 2 and causing uneven penetration, or insufficient grouting pressure resulting in poor penetration. At the same time, grouting pipe 3 is slowly lifted at a preset lifting speed to ensure that the penetration radius is controlled within the allowable range. Preferably, the minimum penetration diameter is 3m to ensure sufficient solid body for installing the foundation pile.

[0069] Step S403: After the grouting depth meets the grouting end standard, the grouting is stopped. After grouting one grouting hole 2, the grouting continues to other grouting holes 2, and the pressure of subsequent grouting is increased. After all grouting holes 2 are completed, the holes are sealed.

[0070] Specifically, the grouting equipment can be a GTZ6O / 21O high-pressure grouting machine.

[0071] In one embodiment, the grouting pipe 3 is a single-flower pipe.

[0072] In this embodiment of the invention, single-tube grouting is used, with a tube length of 100cm. The diameter and spacing of the holes are determined based on on-site test holes (within a 3m grouting range, the spacing is 500mm, and 4 holes are arranged for grouting). The outer diameter of the grouting pipe is 2.5cm. During grouting, the grouting speed and end time are determined by analyzing the PQ instrument on the grouting equipment. The injection volume is calculated based on the penetration radius and consolidation volume, specifically using the formula Q=πR2Hβα, where R is the penetration radius; H is the cave height; α is the over-grouting coefficient; and β is the filling coefficient. These parameters and coefficients can be determined based on on-site tests.

[0073] In one embodiment, the preset pressure range is 0.5 MPa to 1.0 MPa.

[0074] In this embodiment of the invention, the grouting pressure is controlled between 0.5MPa and 1.0MPa to avoid excessive grouting pressure damaging the sidewall structure of the grouting hole 2 and causing uneven penetration, or insufficient grouting pressure resulting in poor penetration. The maximum pressure is 1.5MPa. When the grouting pressure exceeds 1.5MPa, grouting can be stopped.

[0075] In one embodiment, the preset grouting speed is 15L / min to 20L / min.

[0076] In this embodiment of the invention, the grouting speed is controlled at 15L / min to 20L / min to avoid uneven grout penetration due to excessively fast grouting speed, or low construction efficiency and easy solidification of the previously injected grout, which affects uniformity.

[0077] In one embodiment, the slurry comprises cement slurry and water glass.

[0078] In this embodiment of the invention, the grout uses a dual-grout 8, which forms a high-strength aggregate after grouting, effectively reinforcing the soil and improving its density and strength. The water glass content can be determined by on-site testing according to actual needs. By changing the water glass content, the setting time of the grout can be changed, achieving rapid setting and improving construction efficiency.

[0079] As an alternative implementation, the grout may include cement mortar and water glass. Using a dual-grout mixture (8), the resulting grout has high strength, effectively reinforcing the soil and improving its density and strength. This allows for a reduction in grouting depth to meet structural strength requirements. The process is simple, streamlined, and cost-effective. The water glass content can be determined through on-site testing based on actual needs. By changing the water glass content, the setting time of the grout can be altered, achieving rapid setting and improving construction efficiency.

[0080] Alternatively, the slurry can be cement slurry.

[0081] Alternatively, the grout can be cement mortar.

[0082] Specifically, the cement slurry mix ratio is water:cement = 0.5:1, and the cement is preferably PO-42.5 grade cement.

[0083] Specifically, the cement mortar mix ratio is water:cement:sand = 1:1:0.8, and the cement is preferably PO-42.5 grade cement.

[0084] In one embodiment, the grouting depth ranges from 3m to 4m from the bottom of the layer of unknown origin.

[0085] It should be noted that the strata in the borehole, from top to bottom, consist of: 4. Plain fill layer; 5. Silty clay layer; 6. Strongly weathered silty mudstone layer; 7. Layer of unknown origin; and 8. Slightly weathered limestone layer.

[0086] In this embodiment of the invention, the grouting depth ranges from 3m to 4m at the bottom of strata of unknown origin or strata with lava development. Under the premise of ensuring structural strength, excessive grouting depth is avoided to prevent grout waste and increase construction difficulty.

[0087] In one embodiment, the grouting termination criterion is when the grouting volume is less than 20 L / min, the grouting pressure reaches 0.5 to 1.0 MPa, and this condition is maintained for 10 minutes.

[0088] Alternatively, the grouting termination criterion is when the grouting pressure reaches 1.0–1.5 MPa and the grout is difficult to inject;

[0089] Alternatively, the grouting termination standard is when the grouting volume of a single hole reaches more than 1.5 times the average grouting volume (the specific value can be determined according to the actual construction situation, preferably 1.5 to 2.0 times), and the grouting volume is significantly reduced;

[0090] Alternatively, the grouting completion criterion is if grouting reaches 30m. 3 If no pressure rise occurs, stop grouting and wait for the grout to harden before continuing grouting. Repeat this process until the grouting reaches the preset depth.

[0091] In this embodiment of the invention, during the grouting process, when the grouting reaches any of the above-mentioned grouting end criteria within the grouting depth range, grouting can be stopped to facilitate timely cessation of construction. By effectively controlling the grouting process through the grouting end criteria, the quality of the finished product is improved, the requirements for operators are reduced, it is easy to implement, and construction efficiency is ensured.

[0092] like Figure 2As shown in the figure, there are single pile grouting areas and three pile grouting areas, where L1 is a layer of unknown origin and L2 is the grouting area. Taking the use of double grout 8 as an example, the specific construction process of the local grouting method provided in this embodiment of the invention is as follows: First, based on the existing coordinate control points of the project, the geological survey report, and the construction survey data, the positioning hole 1 at the center of the grouting hole 2 is determined using a theodolite. The geological conditions are controlled according to the advance drilling reaction. Grouting holes 2 are evenly arranged around the pile hole wall as the center, according to the diameter of the pile. The grout penetrates halfway... The diameter is pre-controlled at 0.3m, with multiple grouting holes 2 arranged in an interlocking pattern. Then, based on the hole positions of the grouting holes 2, impact drilling is used to obtain soil cores from the entire hole. If karst caves or fluid fillers are present, it is considered a "drill drop," and drilling must continue until a hard layer is reached, at which point drilling stops. Next, a lower steel pipe is installed inside the grouting hole 2 to support the sidewalls, facilitating the removal of mud and sediment. Then, a steel casing is lowered, with its top sealed to the grout delivery hose of the grouting equipment, and at least one of sand or gravel is injected to form a filler. Next, grouting is performed using grouting pipe 3, which is inserted to the bottom of the filler. The grouting pressure is controlled at 0.5MPa~1.0MPa, and the grouting speed is controlled at 15L / min~20L / min. Grout is injected into the grouting hole 2 through grouting pipe 3 in an intermittent grouting manner. Each grouting is performed after the grout from the previous grouting has initially bonded with the filler. During grouting, grouting pipe 3 is slowly raised at a preset lifting speed to ensure a minimum penetration diameter of 3m. Grouting is repeated multiple times. During the grouting process, the grouting... In areas with poor grouting results, supplementary grouting should be carried out, and ground monitoring should be strengthened and records kept. Grouting should be suspended near existing railway lines and buildings when surface rise / fall reaches 10 mm / d or horizontal displacement exceeds 5 mm / d. During grouting, if the grouting volume is less than 20 L / min, the grouting pressure reaches 0.5–1.0 MPa and remains at that pressure for 10 minutes, the grouting pressure reaches 1.0–1.5 MPa and the grout is difficult to inject, the grouting volume in a single hole reaches more than 1.5 times the average grouting volume and the grouting volume decreases significantly, or if grouting reaches 30 m... 3 If no pressure increase occurs, grouting is stopped. After the grout hardens, grouting resumes. When the above-mentioned grouting completion criteria are met, and the grouting area is 3m-4m below the bottom of the layer of unknown cause, grouting ends, and the next grouting hole is started. This process continues until all grouting holes are completed and solidified, at which point backfilling is performed. The local grouting method provided in this embodiment reduces grouting depth, simplifies operation, optimizes procedures, reduces costs, reduces the number of grouting hole locations, shortens the construction period, lowers the operational requirements for operators, is easy to implement, allows for effective control during the grouting process, and improves the quality of the finished product.

[0093] Although embodiments of the invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A local grouting construction process, characterized in that, Applied to strata of unknown origin or strata with developed lava, the process includes the following steps: Measurement of drilling location: Based on the existing coordinate control points of the project, geological survey report and construction survey data, the positioning hole (1) of the center position of the grouting hole (2) is determined by the theodolite, and the hole position of the grouting hole (2) is determined based on the positioning hole (1); Drilling: Percussion drilling was used according to the position of the grouting hole (2), and soil cores were taken from the whole hole until the hard layer was reached and then drilling was stopped; Hole cleaning: After the grouting hole (2) is formed, a steel casing is installed to remove the mud and sediment inside the hole; Grouting: The steel sleeve is placed at the bottom, and the prepared grout is injected into the pre-set position in the grouting hole (2) using grouting equipment. The grouting ends after the grouting end standard is met within the grouting depth range, until the grouting of all grouting holes (2) is completed. After grouting is completed, wait for the grout to solidify and then backfill the grouting hole (2).

2. The local grouting construction process according to claim 1, characterized in that, The process of determining the positioning hole (1) of the center position of the grouting hole (2) using a theodolite based on the existing coordinate control points, geological survey report, and construction survey data, and determining the hole position of the grouting hole (2) based on the positioning hole (1) specifically includes the following steps: Based on the existing coordinate control points, geological survey report and construction survey data of the project, the positioning hole (1) at the center position of the grouting hole (2) was determined by the theodolite; Centered on the positioning hole (1), the number and diameter of the grouting holes (2) are determined according to the diameter of the foundation pile; the holes of multiple grouting holes (2) are evenly arranged around the positioning hole (1) on the outer ring of the foundation pile, and the multiple grouting holes (2) are interlocked with each other.

3. The local grouting construction process according to claim 1, characterized in that, The lower steel sleeve is injected with the prepared grout at a pre-set position in the grouting hole (2) using grouting equipment. Grouting ends after the grouting end standard is met within the grouting depth range, until all grouting holes (2) are grouted. The specific steps include: A lower steel casing is installed, the top of which is sealed to the grout delivery hose of the grouting equipment, and at least one of sand or gravel is poured in to form a filler. Grouting is performed using a grouting pipe (3), which is inserted to the bottom of the filler. The grouting equipment injects grout into the grouting hole (2) through the grouting pipe (3) in an intermittent grouting manner within the preset pressure range. Each grouting is performed after the grout from the previous grouting has initially bonded with the filler. During grouting, the grouting pipe (3) is slowly lifted at the preset lifting speed while grouting at the preset grouting speed. The grouting is repeated multiple times. Grouting ends after the grouting depth meets the grouting end standard. After grouting one grouting hole (2), grouting continues for other grouting holes (2), and the pressure of subsequent grouting is increased. After all grouting holes (2) are completed, the holes are sealed.

4. The local grouting construction process according to claim 3, characterized in that, The grouting pipe (3) is a single-flower pipe.

5. The local grouting construction process according to claim 3, characterized in that, The preset pressure range is 0.5MPa to 1.0MPa.

6. The local grouting construction process according to claim 3, characterized in that, The preset grouting speed is 15L / min to 20L / min.

7. The local grouting construction process according to claim 1, characterized in that, The slurry includes cement slurry and water glass.

8. The local grouting construction process according to claim 1, characterized in that, The grout comprises cement mortar and water glass.

9. The local grouting construction process according to claim 1, characterized in that, The grouting depth ranges from 3m to 4m at the bottom of strata of unknown origin or strata with lava development.

10. The local grouting construction method according to any one of claims 1 to 9, characterized in that, The grouting termination criteria are: the grouting volume is less than 20 L / min, the grouting pressure reaches 0.5 to 1.0 MPa, and this pressure is maintained for 10 minutes. Alternatively, the grouting termination criterion is when the grouting pressure reaches 1.0–1.5 MPa and the grout is difficult to inject; Alternatively, the grouting termination criterion is when the grouting volume in a single hole reaches more than 1.5 times the average grouting volume, and the grouting volume decreases significantly; Alternatively, the grouting completion criterion is if grouting reaches 30m. 3 If no pressure rise occurs, stop grouting and wait for the grout to harden before continuing grouting. Repeat this process until the grouting reaches the preset depth.

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