Construction method for post-grouting of high-pile wharf cast-in-place pile through sounding pipe

Abstract

The invention discloses a construction method for post-grouting of a high-pile wharf cast-in-place pile through a sounding pipe, and relates to the technical field of building construction, the construction method comprises the steps that a reinforcement cage and a pile end grouting pipe are installed, the grouting pipe is dredged, a grouting valve is opened, the dredging time of the grouting pipe is 24 h after concrete pouring, and the grouting valve is burst open by injecting pressure water into the grouting pipe; and the pile end is grouted, and grouting is stopped. According to the construction method for post-grouting of the high-pile wharf cast-in-place pile through the sounding pipe, the one-way grouting valve is additionally arranged at the bottom of the ultrasonic detection pipe, the working principle is simple, the form is simple, it is avoided that holes are drilled or grouting pipes are buried in the pile body again, the grouting valve is drilled through high-pressure water at proper time, and the construction efficiency is improved. The influence on the concrete strength and the pile body integrity is extremely small.

Description

Technical Field

[0001] The invention relates to the technical field of building construction, in particular to a construction method for post-grouting of cast-in-place piles of a high-pile wharf by using an acoustic detection tube. Background Art

[0002] The high-pile wharf is a hollow structure with a simple structure and clear force. Its upper beam-slab structure constitutes the wharf surface and is connected to the pile foundation as a whole. It directly bears the vertical and horizontal loads acting on the wharf surface and transfers them to the pile foundation. The pile foundation is used to support the upper structure and transfer the load of the upper structure and the wharf surface to the deep foundation. It is also conducive to stabilizing the slope. It is suitable for various complex geological conditions, especially soft soil foundations. Rock-embedded piles can be used on rock foundations, and have little impact on water flow. It is a type of wharf structure that is currently used more in my country. As one of the main types of pile foundations, cast-in-place piles have been increasingly widely used in high-pile wharves in recent years due to their universality to various types of engineering geology.

[0003] The existing grouting method for high-pile docks is cumbersome to construct, requires the use of a mixer, requires manpower and consumes a large amount of water, and the vertical ultimate bearing capacity of a single cast-in-place pile is insufficient.

[0004] Therefore, it is urgent to improve this shortcoming. The present invention studies and improves the existing structure and shortcomings, and provides a construction method for post-grouting of cast-in-place piles of a high-pile wharf using an acoustic detection tube. Summary of the invention

[0005] The object of the present invention is to provide a construction method for post-grouting of cast-in-place piles of a high-pile wharf by using an acoustic detection tube, so as to solve the problems raised in the above-mentioned background technology.

[0006] To achieve the above object, the present invention provides the following technical solution: a construction method for post-grouting of high-pile wharf bored piles using an acoustic detection tube, the construction method comprising the following steps:

[0007] Step 1: Install the steel cage and the pile end grouting pipe. The grouting pipe and the steel cage are placed simultaneously. Five grouting pipes are evenly arranged close to the inner side of the steel cage and tied with wire every 3 meters to prevent them from falling off. The grouting pipe is 0.3 to 0.4 meters longer than the steel cage. The grouting valve at the tail of the grouting pipe is inserted into the bearing layer at the bottom of the hole.

[0008] Step 2: Clear the grouting pipe and open the grouting valve. The grouting pipe should be cleared 24 hours after concrete pouring. The grouting valve should be flushed open by injecting pressurized water into the grouting pipe.

[0009] Step 3: Grouting of the pile end should be carried out within 2 to 30 days after the concrete pouring is completed, and an intelligent grouting machine should be used to mix and stir the cement slurry;

[0010] Step 4: Terminate grouting. After the grouting termination conditions are determined by on-site tests, the grouting can be stopped, the grouting joints can be removed, and the grouting pipes can be cleaned.

[0011] Furthermore, the pile diameters of the bored piles are 2.3m and 2.5m. When the grouting pipe is installed, the steel bars at the bottom of the steel cage at the grouting pipe installation position are extended to 20 to 30mm above the grouting valve to prevent the grouting valve from directly touching the bottom, so as to protect the grouting valve. After the concrete of the bored pile is poured and initially set, a grouting press is used to press clean water into the grouting pipe to flush out the concrete wrapping the grouting valve to prevent the grouting channel from being blocked due to the concrete strength reaching a certain level.

[0012] Furthermore, a grouting valve is installed at one end of the grouting pipe, and the grouting valve adopts a one-way grouting valve. At the same time, the grouting valve is used as a grouting device. The grouting hole of the grouting valve should be wrapped and sealed with waterproof tape before use to prevent cement slurry from entering the grouting valve and causing blockage.

[0013] Furthermore, one end of the one-way grouting valve is threadedly connected to a connecting section, and the one-way grouting valve includes a sleeve, a piston, a spring and a plug. The surface of the sleeve is provided with a grouting hole, and a piston is installed inside the sleeve. A spring is installed on one side of the piston. The end of the sleeve away from the connecting section is threadedly connected to a plug.

[0014] Furthermore, a steel cage support frame is installed inside the steel cage, and 5 ultrasonic detection tubes are distributed in a circular array around the center of the cross-section of the steel cage. The ultrasonic detection tubes also serve as post-grouting tubes and are securely tied to the steel cage with wire.

[0015] Furthermore, the one-way grouting valve and the ultrasonic detection tube are threadedly connected by a connecting section, and the connecting section is a galvanized steel pipe. At the same time, the ultrasonic detection tube adjusts the depth of the one-way grouting valve entering the bearing layer at the bottom of the pile through the connecting section. The top of the ultrasonic detection tube is connected to a grouting nozzle and is connected to the grouting equipment through a grouting pipe.

[0016] Furthermore, in the step 1, when each section of the steel cage is lowered, clean water is injected into the grouting pipe to check the sealing performance of the pipeline. When the grouting pipe is filled with clean water, the requirement is met by keeping the water level stable and not dropping.

[0017] Furthermore, in the grouting of the pile end in the step three, 42.5 grade cement slurry is used for grouting, 5 grouting pipes are set for each pile, the grouting pipes enter the soil at the bottom of the pile by 300 to 400 mm, the cement slurry is stirred according to the mix ratio, the water-cement ratio is controlled between 0.5 and 0.6, the cement slurry specific gravity is controlled between 1.98 and 1.75, and the stirred cement slurry is filtered with a filter with a pore size not greater than 3×3 mm.

[0018] Furthermore, the grouting pressure is controlled at 1.0 MPa, and the grouting flow rate is not less than 75 L / min.

[0019] Furthermore, the grouting volume is controlled according to the following requirements: 7.0t for a 2300mm diameter bored pile and 8.0t for a 2500mm diameter bored pile. Grouting is terminated when any of the following conditions are met, and the grouting termination conditions are:

[0020] a. The grouting volume of the 2300mm diameter cast-in-place pile reaches 7.0t, and the grouting volume of the 2500mm diameter cast-in-place pile reaches 8.0t;

[0021] b. The total grouting volume has reached 75% of the original design grouting volume and the grouting pressure has exceeded 10MPa;

[0022] c. If cement slurry is found to be oozing out from around the pile, wait for 30 minutes before switching to other grouting pipes for grouting until the grouting volume reaches requirement a or cement slurry is oozing out from around the pile.

[0023] The present invention provides a construction method for post-grouting of high-pile wharf cast-in-place piles using an acoustic detection tube, which has the following beneficial effects:

[0024] 1. The present invention adds a one-way grouting valve at the bottom of the ultrasonic detection tube, which has a simple working principle and a simple form, and avoids drilling holes or burying grouting pipes in the pile body again. The grouting valve is opened with high-pressure water at an appropriate time, which has little effect on the concrete strength and the integrity of the pile body.

[0025] 2. The present invention adopts intelligent grouting machine equipment to realize the integrated construction of intelligent preparation of cement slurry mix ratio, mixing and grouting, avoiding the need for manual estimation of water consumption using a mixer in traditional processes, so that the quality of post-grouting construction is effectively guaranteed.

[0026] 3. The present invention has been verified through experiments, and the grouting effect is remarkable. The vertical ultimate bearing capacity of the bored pile in this project is increased by about 37%, and the maximum test load settlement is reduced by about 83%, achieving the expected goal. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic diagram of the installation structure of an ultrasonic detection tube in a construction method of post-grouting of cast-in-place piles of a high-pile wharf using an ultrasonic detection tube according to the present invention;

[0028] Figure 2 The present invention is a structural schematic diagram of a one-way grouting valve in a construction method for post-grouting of cast-in-place piles of a high-pile wharf using an acoustic detection tube.

[0029] In the figure: 1. steel cage; 2. steel cage support frame; 3. ultrasonic detection tube; 4. connecting section; 5. one-way grouting valve; 501. sleeve; 502. spring; 503. piston; 504. plug; 505. grouting hole. DETAILED DESCRIPTION

[0030] The following embodiments of the present invention are described in further detail in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0031] like Figure 1 and Figure 2 As shown, a construction method for post-grouting of high-pile wharf cast-in-place piles using an acoustic detection tube includes the following steps:

[0032] Step 1: Install the steel cage 1 and the pile end grouting pipe, wherein the grouting pipe and the steel cage 1 are placed simultaneously, 5 grouting pipes are evenly arranged close to the inner side of the steel cage 1, and are tied with wire every 3 meters to prevent falling off. The grouting pipe is 0.3-0.4 meters longer than the steel cage 1, and the grouting valve at the tail of the grouting pipe is inserted into the bearing layer at the bottom of the hole;

[0033] Step 2: Clear the grouting pipe and open the grouting valve. The grouting pipe should be cleared 24 hours after concrete pouring. The grouting valve should be flushed open by injecting pressurized water into the grouting pipe.

[0034] Step 3: Grouting of the pile end should be done within 2 to 30 days after the concrete pouring is completed, and an intelligent grouting machine should be used to proportion and mix the cement slurry. If the age is too long, the risk of the injection hole not being able to open will increase; if grouting is done too early, the pile end is likely to be damaged by the grouting pressure, affecting the improvement of the concrete strength at the pile end. The acoustic detection pipe of this project also serves as a grouting pipe. Grouting at the pile end should be carried out after the ultrasonic testing of the pile foundation is completed and the test results meet the design and specification requirements. If the concrete age is too long, a secondary water pressure test should be carried out on the grouting pipe to check whether the grouting valve is blocked;

[0035] Step 4: Terminate grouting. After the grouting termination conditions are determined by on-site tests, the grouting can be stopped, the grouting joints can be removed, and the grouting pipes can be cleaned.

[0036] The LZLQ-500 intelligent grouting machine is selected as the post-grouting equipment. The maximum grouting pressure can reach 16MPa, integrating cement slurry configuration, mixing, grouting and other functions. After the equipment is accepted on site, the quality assurance information, certificate, list and other materials are moved to the site for use, and the pressure gauge and measuring container are calibrated. Through digital, precise and efficient control construction, the cement slurry required for post-grouting can be accurately controlled, and precise operations can be performed according to the required grouting amount. The grouting parameters can be observed in real time, which is convenient for the adjustment of the construction process. At the same time, it greatly reduces the investment of construction personnel and reduces construction costs.

[0037] The pile diameters of the bored piles are 2.3m and 2.5m. When installing the grouting pipe, the steel bars at the bottom of the steel cage 1 at the grouting pipe installation position are extended to 20 to 30mm above the grouting valve to prevent the grouting valve from directly touching the bottom and protect the grouting valve. After the concrete of the bored pile is poured and initially set, a grouting press is used to press clean water into the grouting pipe to flush out the concrete wrapped around the grouting valve to prevent the grouting channel from being blocked due to the concrete strength reaching a certain level.

[0038] A grouting valve is installed at one end of the grouting pipe, and the grouting valve adopts a one-way grouting valve 5. At the same time, the grouting valve is used as a grouting device. The grouting hole of the grouting valve should be wrapped and blocked with waterproof tape before use to prevent cement slurry from entering the grouting valve and causing blockage.

[0039] One end of the one-way grouting valve 5 is threadedly connected to the connecting section 4, and the one-way grouting valve 5 includes a sleeve 501, a piston 502, a spring 503 and a plug 504. The surface of the sleeve 501 is provided with a grouting hole 505, and the piston 502 is installed inside the sleeve 501. A spring is installed on one side of the piston 502. The end of the sleeve 501 away from the connecting section 4 is threadedly connected to the plug 504.

[0040] A steel cage support frame 2 is installed inside the steel cage 1, and five ultrasonic detection tubes 3 are distributed in a circular array around the cross-sectional center of the steel cage 1. The ultrasonic detection tubes 3 also serve as post-grouting tubes and are securely tied to the steel cage 1 with wire.

[0041] The one-way grouting valve 5 and the ultrasonic detection tube 3 are threadedly connected by a connecting section 4, and the connecting section 4 is a galvanized steel pipe. At the same time, the ultrasonic detection tube 3 adjusts the one-way grouting valve 5 to enter the bearing layer of the pile bottom through the connecting section 4. The top of the ultrasonic detection tube 3 is connected to a grouting nozzle and is connected to the grouting equipment through a grouting pipe.

[0042] In step 1, when each section of the steel cage 1 is lowered, clean water is injected into the grouting pipe to check the sealing performance of the pipeline. When the grouting pipe is filled with clean water, the requirement is met by keeping the water level stable and not dropping.

[0043] In step 3, 42.5 grade cement slurry is used for grouting the pile end to ensure that the cement is fresh and not agglomerated. Five grouting pipes are set for each pile, and the grouting pipes enter the soil at the bottom of the pile by 300-400mm. The cement slurry is stirred according to the mix ratio, and the water-cement ratio is controlled between 0.5 and 0.6. The specific gravity of the cement slurry is controlled between 1.98 and 1.75. The stirred cement slurry is filtered with a filter with an aperture of no more than 3×3mm. The grouting must be controlled from bottom to top. The infiltration is controlled during grouting to ensure slow speed, low pressure and low flow, so that the cement slurry can naturally penetrate into the soil layer;

[0044] When connecting the grouting pipe, the sealing, rigidity and stability should be ensured. A water flow test should be carried out after each section of the grouting pipe is lowered into place. When the grouting pipe is blocked, additional pressure grouting must be carried out.

[0045] The grouting pressure is controlled at 1.0MPa and the grouting flow rate is not less than 75L / min.

[0046] The grouting volume is controlled according to the following requirements: 7.0t for a 2300mm diameter bored pile and 8.0t for a 2500mm diameter bored pile. Grouting is terminated when any of the following conditions are met:

[0047] a. The grouting volume of the 2300mm diameter cast-in-place pile reaches 7.0t, and the grouting volume of the 2500mm diameter cast-in-place pile reaches 8.0t;

[0048] b. The total grouting volume has reached 75% of the original design grouting volume and the grouting pressure has exceeded 10MPa;

[0049] c. If cement slurry is found to be oozing out from around the pile, wait for 30 minutes before switching to other grouting pipes for grouting until the grouting volume reaches requirement a or cement slurry is oozing out from around the pile.

[0050] In order to verify the effect of post-grouting on improving the vertical ultimate bearing capacity of a single cast-in-place pile, and to check the geological data, pile foundation bearing capacity and construction technology, two test piles were selected for static load test using the anchor pile method. One pile was tested twice, the first time before post-grouting and the second time after post-grouting. The other pile was tested directly after grouting. The test results are detailed in the following table:

[0051]

[0052] After test comparison, the grouting effect is significant. The vertical ultimate bearing capacity of a single bored pile in this project has increased by about 37%, and the maximum test load settlement has decreased by about 83%.

[0053] The embodiments of the present invention are given for the purpose of illustration and description, and are not intended to be exhaustive or to limit the invention to the disclosed forms. Many modifications and variations will be apparent to those of ordinary skill in the art. The embodiments are selected and described in order to better illustrate the principles and practical applications of the present invention and to enable those of ordinary skill in the art to understand the present invention and thereby design various embodiments with various modifications suitable for specific uses.

Claims

1. A construction method for post-grouting of cast-in-place piles of high-pile docks using an acoustic detection tube, characterized in that: The construction method comprises the following steps: Step 1: Install the steel cage and the pile end grouting pipe. The grouting pipe and the steel cage are placed simultaneously. Five grouting pipes are evenly arranged close to the inner side of the steel cage and tied with wire every 3 meters to prevent them from falling off. The grouting pipe is 0.3 to 0.4 meters longer than the steel cage. The grouting valve at the tail of the grouting pipe is inserted into the bearing layer at the bottom of the hole. Step 2: Clear the grouting pipe and open the grouting valve. The grouting pipe should be cleared 24 hours after concrete pouring. The grouting valve should be flushed open by injecting pressurized water into the grouting pipe. Step 3: Grouting of the pile end should be carried out within 2 to 30 days after the concrete pouring is completed, and an intelligent grouting machine should be used to mix and stir the cement slurry; Step 4: Terminate grouting. After the grouting termination conditions are determined by on-site tests, the grouting can be stopped, the grouting joints can be removed, and the grouting pipes can be cleaned.

2. The construction method of high-pile wharf bored piles using an acoustic detection tube for post-grouting according to claim 1, characterized in that: The pile diameters of the bored piles are 2.3m and 2.5m. When the grouting pipe is installed, the steel bars at the bottom of the steel cage at the grouting pipe installation position are extended to 20-30mm above the grouting valve to prevent the grouting valve from directly touching the bottom, so as to protect the grouting valve. After the concrete of the bored pile is poured and initially set, a grouting press is used to press clean water into the grouting pipe to flush out the concrete wrapped around the grouting valve to prevent the grouting channel from being blocked due to the concrete strength reaching a certain level.

3. The construction method of high-pile wharf bored piles using an acoustic detection tube for post-grouting according to claim 2, characterized in that: A grouting valve is installed at one end of the grouting pipe, and the grouting valve adopts a one-way grouting valve. At the same time, the grouting valve is used as a grouting device. Before use, the grouting hole of the grouting valve should be wrapped and sealed with waterproof tape to prevent cement slurry from entering the grouting valve and causing blockage.

4. The construction method of high-pile wharf bored piles using an acoustic detection tube for post-grouting according to claim 3, characterized in that: One end of the one-way grouting valve is threadedly connected to a connecting section, and the one-way grouting valve includes a sleeve, a piston, a spring and a plug. The surface of the sleeve is provided with a grouting hole, and a piston is installed inside the sleeve. A spring is installed on one side of the piston. One end of the sleeve away from the connecting section is threadedly connected to a plug.

5. The construction method of high-pile wharf bored piles using an acoustic detection tube for post-grouting according to claim 4, characterized in that: A steel cage support frame is installed inside the steel cage, and 5 ultrasonic detection tubes are distributed in a circular array around the center of the cross-section of the steel cage. The ultrasonic detection tubes also serve as post-grouting tubes and are securely tied to the steel cage with wire.

6. The construction method of high-pile wharf bored piles using an acoustic detection tube for post-grouting according to claim 1, characterized in that: The one-way grouting valve and the ultrasonic detection tube are connected by a threaded connection section, and the connection section is a galvanized steel pipe. At the same time, the ultrasonic detection tube adjusts the depth of the one-way grouting valve entering the bearing layer at the bottom of the pile through the connection section. The top of the ultrasonic detection tube is connected to the grouting nozzle and connected to the grouting equipment through the grouting pipe.

7. The construction method of high-pile wharf bored piles using an acoustic detection tube for post-grouting according to claim 1, characterized in that: In the step 1, when each section of the steel cage is lowered, clean water is injected into the grouting pipe to check the sealing performance of the pipeline. When the grouting pipe is filled with clean water, the requirement is met by keeping the water level stable and not dropping.

8. The construction method of high-pile wharf bored piles using an acoustic detection tube for post-grouting according to claim 1, characterized in that: In the grouting of the pile end in the step three, 42.5 grade cement slurry is used for grouting, 5 grouting pipes are set for each pile, and the grouting pipes enter the soil at the bottom of the pile by 300-400 mm. The cement slurry is stirred according to the mix ratio, the water-cement ratio is controlled between 0.5 and 0.6, and the cement slurry specific gravity is controlled between 1.98 and 1.

75. The stirred cement slurry is filtered with a filter with a pore size not greater than 3×3 mm.

9. The construction method of high-pile wharf bored piles using an acoustic detection tube for post-grouting according to claim 1, characterized in that: The grouting pressure is controlled at 1.0 MPa, and the grouting flow rate is not less than 75 L / min.

10. The construction method of high-pile wharf bored piles using an acoustic detection tube for post-grouting according to claim 1, characterized in that: The grouting volume is controlled according to the following requirements: 7.0t for a 2300mm diameter cast-in-place pile and 8.0t for a 2500mm diameter cast-in-place pile. Grouting is terminated when any of the following conditions are met: a. The grouting volume of the 2300mm diameter cast-in-place pile reaches 7.0t, and the grouting volume of the 2500mm diameter cast-in-place pile reaches 8.0t; b. The total grouting volume has reached 75% of the original design grouting volume and the grouting pressure has exceeded 10MPa; c. If cement slurry is found to be oozing out from around the pile, wait for 30 minutes before switching to other grouting pipes for grouting until the grouting volume reaches requirement a or cement slurry is oozing out from around the pile.

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