Alternate grouting type cement jet grouting pile construction device and magnetic mark pile length detection method

Abstract

The invention relates to the technical field of pile foundation detection, in particular to an alternate grouting type cement jet grouting pile construction device and a magnetic mark pile length detection method.The alternate grouting type cement jet grouting pile construction device comprises a drilling machine platform, the drilling machine platform is provided with a drilling rod, a grouting stirring head is arranged at the bottom of the drilling rod, and a first nozzle and a second nozzle are formed in the surface of the grouting stirring head; a first channel connected with the first nozzle and a second channel connected with the second nozzle are arranged in the drill rod. The two grouting channels and the two nozzles are arranged on the guniting stirring head, different kinds of slurry can be injected into the jet grouting pile through the nozzles by using the independent slurry mixing bin and the slurry pump, especially two columns which are arranged at intervals and have different properties can be formed, iron powder is arranged in one of the columns, and therefore the two kinds of slurry can be injected into the jet grouting pile through the nozzles. The magnetic mark can be formed, the magnetic field corresponding to the column body can be detected through the magnetoresistive sensor, and the length and uniformity of the pile body can be judged through the detected magnetic field by reasonably arranging the distribution of the column body.

Description

Technical Field

[0001] The present invention relates to the technical field of pile foundation detection, in particular to an alternate grouting type cement rotary jet pile construction device and a magnetic marker pile length detection method. Background Art

[0002] Cement jet grouting piles, a key technology for foundation reinforcement, use high-pressure jetting of cement-based slurry mixed with soil to form a continuous, uniform consolidation mass. They are widely used in soft soil treatment, foundation pit support, and reinforcement of existing building foundations. Their construction process relies on drilling rig pilot hole positioning and staged lifting and jetting to achieve layer-by-layer pile formation. As underground projects expand into complex geological conditions and deeper spaces, the design depth and quality control requirements for jet grouting piles are increasing, driving the development of automated construction techniques with refined parameters.

[0003] In the pile quality acceptance process, the length of the pile body is one of the core indicators, which directly affects the assessment of bearing capacity and deformation characteristics. Traditional length detection mostly relies on construction record review, low-strain stress wave reflection method or drilling coring verification. Among them, the stress wave method infers the position of the pile bottom by analyzing the reflection signal of the elastic wave excited by the pile top, but its accuracy is affected by factors such as the difference in pile-soil impedance and interference from shallow defects; the drilling coring method has the limitations of destroying the integrity of the pile body, high cost and difficulty in full coverage detection. In recent years, non-destructive testing technologies based on electromagnetic induction and geological radar have been gradually introduced into pile foundation projects, but their adaptability to low-conductivity and inhomogeneous materials such as cement-soil piles still needs to be improved. Summary of the Invention

[0004] In view of the technical problems existing in the prior art of jet grouting piles, the first aspect of the present invention provides an alternating grouting type cement jet grouting pile construction device, comprising:

[0005] A drilling rig platform, wherein the drilling rig platform is provided with a drill rod, a shotcrete mixing head is provided at the bottom of the drill rod, a first nozzle and a second nozzle are provided on the surface of the shotcrete mixing head, a first channel connected to the first nozzle and a second channel connected to the second nozzle are provided in the drill rod, and the drilling rig platform is used to drive the drill rod to rotate at a predetermined speed and feed along its axis, so that the shotcrete mixing head drills from the surface to a target depth;

[0006] a slurry supply component, comprising a first slurry mixing bin and a second slurry mixing bin, wherein the first slurry mixing bin is used to store a first slurry, and the second slurry mixing bin is used to store a second slurry, and the outlet of the first slurry mixing bin is provided with a first mud pump, and the first mud pump is used to deliver the first slurry to the first channel inlet of the drill pipe, and the outlet of the second slurry mixing bin is provided with a second mud pump, and the second mud pump is used to deliver the second slurry to the second channel inlet of the drill pipe;

[0007] The first slurry comprises a mixed slurry of cement and water, and the second slurry comprises a mixed slurry of cement, iron powder and water;

[0008] During the process of lifting the drill rod from the target depth to the surface, the first mud pump and the second mud pump alternately provide the first slurry and the second slurry to the drill rod, and the spraying mixing head alternately sprays the first slurry and the second slurry during the upward lifting process, so that the formed jet grouting pile includes alternately distributed first columns and second columns, wherein the second column contains iron powder.

[0009] Preferably, the output pressure of the second mud pump is P2, and the output pressure of the first mud pump is P1, wherein P2 = 105% to 110% of P1.

[0010] Preferably, the start and stop times of the first mud pump and the second mud pump are set to be related to the drilling depth of the drill rod. When the drill rod is in the depth range of the first column, the first mud pump remains on and the second mud pump remains off. When the drill rod is in the depth range of the second pile body, the second mud pump remains on and the first mud pump remains off.

[0011] Preferably, the first nozzle and the second nozzle on the surface of the spray mixing head are located at the same horizontal height.

[0012] Preferably, the height ratio of the first column to the second column is 8:2 to 9:1, and the thickness of the second column is at least 10 cm.

[0013] The second aspect of the present invention provides a technical solution, a magnetic marker pile length detection method, comprising the following steps:

[0014] Step 1: Use the above-mentioned alternating grouting type cement rotary jet pile construction device to construct and form rotary jet piles;

[0015] Step 1: Arrange at least one magnetoresistive sensor above the jet grouting pile;

[0016] Step 1: Start the magnetic resistance sensor to collect the magnetic field strength B of the jet grouting pile;

[0017] Step 1: Detect and mark the peak value of the magnetic field intensity B collected by the magnetoresistive sensor, determine the number and position of the marking area, define the nearest marking area as A1, and the farthest marking area as A k (k=1,2,3...,n);

[0018] Step 5: Calculate the length of the jet grouting pile based on the number of marked areas and the distance between adjacent marked areas.

[0019] Preferably, in step 2, a plurality of magnetoresistive sensors are provided, and the plurality of magnetoresistive sensors are distributed in a ring shape around the axis of the rotary jet pile;

[0020] Each magnetoresistive sensor is numbered C1, C2, C3...Cn.

[0021] Preferably, in step 3, all magnetoresistive sensors are turned on synchronously, and in step 4, the magnetic field strength B collected by each magnetoresistive sensor is measured. i Peak detection and marking are performed on the same marking area (i=1, 2, 3..., n), and the uniformity of the pile body is evaluated based on the magnetic field intensity data collected by different magnetoresistive sensors in the same marking area.

[0022] Compared with the prior art, the advantages of the present invention are:

[0023] The present invention provides two grouting channels and two nozzles on the spraying mixing head, and can use independent slurry mixing chambers and mud pumps to inject different types of slurries into the rotary jet piles through the nozzles. In particular, two types of columns with different properties can be formed at intervals. Iron powder is provided in one of the columns to form a magnetic mark, and the magnetic field corresponding to the column can be detected by a magnetoresistive sensor. By reasonably setting the distribution of the columns, the length and uniformity of the pile body can be determined by the detected magnetic field. Compared with the destructive drilling method and the ultrasonic detection method of the pile length, the detection speed is faster, and it is not affected by groundwater and loose soil layers. It is applicable to various geological conditions such as sand layers and clay. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The accompanying drawings are not intended to be drawn to scale. In the drawings, each identical or nearly identical component shown in various figures may be represented by the same reference numeral. For the sake of clarity, not every component is labeled in every figure. Embodiments of various aspects of the present invention will now be described by way of example and with reference to the accompanying drawings, in which:

[0025] Figure 1 This is a schematic structural diagram of the alternate grouting type cement jet grouting pile construction device of the present invention forming a first column;

[0026] Figure 2 This is a schematic structural diagram of the alternate grouting type cement jet grouting pile construction device of the present invention forming a second column;

[0027] Figure 3 Schematic diagram of the structure of the rotary jet pile formed by the alternate grouting type cement rotary jet pile construction device shown in the present invention;

[0028] Figure 4 This is a schematic structural diagram of the magnetoresistive sensor of the present invention arranged at the top of the jet grouting pile to detect the pile length;

[0029] Figure 5 Schematic diagram of the distribution of magnetoresistive sensors on the top of the jet grouting pile shown in the present invention. DETAILED DESCRIPTION

[0030] In order to better understand the technical content of the present invention, specific embodiments are given and described below with reference to the accompanying drawings.

[0031] {Example 1}

[0032] Combine Figure 1 As shown, the first aspect of the present invention provides an alternating grouting type cement jet grouting pile construction device, which includes a drilling platform 200 and a slurry supply component.

[0033] The drilling rig platform 200 is provided with a drill rod 210, a shotcrete mixing head 220 is provided at the bottom of the drill rod 210, and a first nozzle and a second nozzle are provided on the surface of the shotcrete mixing head 220. A first channel connected to the first nozzle and a second channel connected to the second nozzle are provided in the drill rod 210.

[0034] Furthermore, the drilling rig platform 200 is used to drive the drill rod 210 to rotate at a predetermined speed and feed along its axial direction, so that the spray mixing head 220 drills from the surface to a target depth.

[0035] It should be understood that the shotcrete mixing head 220 is usually configured with a mixing structure at the bottom and a nozzle on the side wall. The drilling rig platform 200 controls the drill rod 210 to drill downward at a predetermined angle, rotation speed and feed speed until the target depth is reached. In the process from the soil surface to the target depth, no slurry is sprayed in the nozzle. When it reaches the bottom, the nozzle of the shotcrete mixing head 220 starts to spray slurry to form a pile bottom structure, and then gradually rises upward until it approaches the soil layer to form a pile head structure.

[0036] Combine Figure 1 As shown, the slurry supply component includes a first slurry mixing bin 310 and a second slurry mixing bin 320. The first slurry mixing bin 310 is used to store the first slurry, and the second slurry mixing bin 320 is used to store the second slurry.

[0037] Among them, the outlet of the first slurry mixing chamber 310 is provided with a first mud pump 311, and the first mud pump 311 is used to transport the first slurry to the first channel inlet of the drill pipe 210. The outlet of the second slurry mixing chamber 320 is provided with a second mud pump 312, and the second mud pump 312 is used to transport the second slurry to the second channel inlet of the drill pipe 210.

[0038] Optionally, the first slurry includes a mixed slurry of cement and water, and the second slurry includes a mixed slurry of cement, iron powder and water.

[0039] Combine Figure 1 and Figure 2 As shown, when the drill pipe 210 is lifted from the target depth to the surface, the first mud pump 311 and the second mud pump 312 alternately provide the first slurry and the second slurry to the drill pipe 210 .

[0040] Combine Figure 3 As shown, the spraying mixing head 220 sprays the first slurry and the second slurry alternately during the upward lifting process, so that the formed jet grouting pile 100 includes alternately distributed first columns 102 and second columns 101, wherein the second columns 101 contain iron powder.

[0041] In this way, by controlling the lengths of the first column 102 and the second column 101 , a second column 101 appears at intervals of a predetermined length throughout the jet grouting pile 100 , which facilitates determining the length of the entire jet grouting pile 100 by detecting the number of second piles 101 in the later stage.

[0042] It should be understood that since the second column 101 contains iron powder, there is a magnetic field at the depth where it is located. The existence of this magnetic field can be detected by a magnetoresistive sensor. The magnetoresistive sensor arranged at the top of the rotary jet pile can detect the peak values of multiple magnetic fields distributed along the axis of the pile body, that is, the number of multiple second columns 101 is detected. Since the spacing between adjacent second columns 101 is a known quantity, the length of the pile body can be obtained by the number of second columns 101.

[0043] In an optional embodiment, the output pressure of the second mud pump 312 is P2, and the output pressure of the first mud pump 311 is P1, wherein P2 = 105% to 110% of P1.

[0044] In this way, the output pressure of the second mud pump 321 is slightly greater than the pressure of the first mud pump 311, so that the ejected second slurry can form a better embedding effect with the soil layer of the outer wall, reducing the sedimentation of the iron powder-containing slurry to other heights, and making the iron powder distribution in the formed second column 101 a ring-shaped or disc-shaped structure of a predetermined thickness, and the magnetic field formed is easier to distinguish.

[0045] In an optional embodiment, the start and stop times of the first mud pump 311 and the second mud pump 312 are set to be related to the drilling depth of the drill pipe 210 .

[0046] In particular, when the drill rod 210 is in the depth range of the first column 102, the first mud pump 311 remains on and the second mud pump 312 remains off; when the drill rod 210 is in the depth range of the second pile body 101, the second mud pump 312 remains on and the first mud pump 311 remains off.

[0047] In this way, when the drill rod 210 is gradually lifted upward from the target depth, whenever it is in the height range of the first column 102, the second slurry delivered by the second mud pump 312 is ejected from the second nozzle to form the first column 102. When it continues to be lifted to the height range of the second column 101, the second mud pump 312 is turned off, and the first slurry delivered by the first mud pump 311 is ejected from the first nozzle to form the second pile body 101. The alternating operation as described above forms an alternating distribution state of the first column 102 and the second column 101.

[0048] The second column 101 is located at the bottom of the pile.

[0049] In an optional embodiment, the first nozzle and the second nozzle on the surface of the shotcrete mixing head 220 are located at the same horizontal height. In this way, when the first nozzle and the second nozzle are switched, slurry can be continuously injected into the soil layer to ensure the integrity of the pile body.

[0050] In an optional embodiment, the height ratio of the first column 102 to the second column 101 is 8:2 to 9:1, and the thickness of the second column 101 is at least 10 cm.

[0051] Specifically, when the thickness of the second column 101 is 10 cm, the thickness of the first column 102 is 90 cm; when the thickness of the second column 101 is 15 cm, the thickness of the first column 102 is 85 cm; when the thickness of the second column 101 is 20 cm, the thickness of the first column 102 is 80 cm.

[0052] In this way, the sum of the thicknesses of the first cylinder 102 and the second cylinder 101 is 1m. If the magnetic field peaks of several second cylinders 101 are detected, it means that the length of the pile is roughly the same as the number of second cylinders 101. For example, if a total of 10 magnetic field peaks of the second cylinders 101 are detected, the length of the jet jet pile is 10m to 11m.

[0053] {Example 2}

[0054] The second aspect of the present invention provides a technical solution, a magnetic marker pile length detection method, comprising the following steps:

[0055] Step 1: Use the above-mentioned alternate grouting type cement jet grouting pile construction device to construct a jet grouting pile 100;

[0056] Step 2: Arrange at least one magnetoresistive sensor 400 above the jet grouting pile 100;

[0057] Step 3: Start the magnetoresistive sensor 400 to collect the magnetic field strength B of the jet grouting pile 100;

[0058] Step 4: Detect and mark the peak value of the magnetic field intensity B collected by the magnetoresistive sensor 400, determine the number and position of the marking area, define the nearest marking area as A1, and the farthest marking area as A k (k=1,2,3...,n);

[0059] Step 5: Calculate the length of the jet grouting pile 100 according to the number of marked areas and the distance between adjacent marked areas.

[0060] In a specific embodiment, the length of the jet grouting pile is defined as 10m, wherein the thickness of the second column 101 is 20cm, and the thickness of the first column 102 is 80cm. The magnetoresistive sensor 400 detects the magnetic field of the plurality of second columns 101, detects a plurality of magnetic field peaks, and marks them as A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, A3, A4, A5, A6, A7, A8, A9, A11, A12, A3, A4, A5, A6, A7, A8, A9, A10 ... 10 Thus, the length of the jet-jet pile 100 is calculated based on the number of detected magnetic field peaks (marking areas) and the spacing between adjacent marking areas, that is, 10*1m=10m.

[0061] Furthermore, in step 2, a plurality of magnetoresistive sensors 400 are provided, and the plurality of magnetoresistive sensors 400 are distributed in a ring shape around the axis of the jet-jet pile 100; each magnetoresistive sensor 400 is numbered C1, C2, C3...Cn.

[0062] Specifically, the magnetoresistive sensors 400 are numbered, combined with Figure 5 As shown, a first magnetoresistance sensor 401 (C1), a second magnetoresistance sensor 402 (C2), a third magnetoresistance sensor 403 (C3) and a fourth magnetoresistance sensor 404 (C4) are arranged around the rotary jet pile 100. The first magnetoresistance sensor 401 (C1), the second magnetoresistance sensor 402 (C2), the third magnetoresistance sensor 403 (C3) and the fourth magnetoresistance sensor 404 (C4) are distributed in a ring shape, and the circumference of their distribution is larger than the diameter of the rotary jet pile 100.

[0063] In an optional embodiment, in step 3, all magnetoresistive sensors 400 are turned on synchronously, and in step 4, the magnetic field strength B collected by each magnetoresistive sensor 400 is measured. i Peak detection and marking are performed for each of the magnetic field intensity data (i=1, 2, 3, ..., n), and the uniformity of the pile body is evaluated based on the magnetic field intensity data collected by different magnetoresistive sensors 400 in the same marking area.

[0064] In a specific embodiment, the peak value of the magnetic field detected by the magnetoresistive sensor numbered C1 is detected and marked to obtain B1 (A11, A12, A13, A14, A15, A16, A17, A18, A19, A1 10), the peak value of the magnetic field detected by the magnetoresistive sensor numbered C2 is detected and marked, and B2 (A21, A22, A23, A24, A25, A26, A27, A28, A29, A2 10 ), the peak value of the magnetic field detected by the magnetoresistive sensor numbered C3 is detected and marked, and B3 (A31, A32, A33, A34, A35, A36, A37, A38, A39, A3 10 ), the peak value of the magnetic field detected by the magnetoresistive sensor number C4 is detected and marked, and B4 (A41, A42, A43, A44, A45, A46, A47, A48, A49, A4 10 ).

[0065] Among them, each marking area corresponds to a magnetic field strength B ij , i represents the number of the magnetoresistive sensor, j represents the number of the marking area, (i = 1, 2, 3, 4; j = 1, 2, 3, 4, 5, 6, 7, 8, 9, 10).

[0066] For any marking area, the magnetic field strength of each magnetoresistive sensor in the marking area is obtained, for example, the third marking area (A13, A23, A33, A43). For the magnetoresistive sensor numbered C1, the magnetic field strength detected in the third marking area is B. 13 , the magnetic field strength of the third marking area detected by the magnetoresistive sensor numbered C2 is B 23 , the magnetic field strength of the third marking area detected by the magnetoresistive sensor numbered C3 is B 33 , the magnetic field strength of the third marking area detected by the magnetoresistive sensor numbered C4 is B 43 .

[0067] As mentioned above, by comparing B 13 、B 23 、B 33 、B 43 and (B 13 +B 23 +B 33 +B 43 ) / 4 can be used to evaluate the uniformity of the pile body. Optionally, if any magnetoresistive sensor detects that the magnetic field strength of the target marking area exceeds 120% of the average value of all magnetic field strengths in the marking area, or is less than 80% of the average value of all magnetic field strengths in the marking area, it indicates that the uniformity of the pile body is abnormal.

[0068] In combination with the above embodiments, the present invention sets two grouting channels and two nozzles in the spraying mixing head, and can use independent slurry mixing chambers and mud pumps to inject different types of slurries into the rotary jet piles through the nozzles. In particular, two types of columns with different properties can be formed at intervals. Iron powder is set in one of the columns to form a magnetic mark, and the magnetic field corresponding to the column can be detected by a magnetoresistive sensor. By reasonably setting the distribution of the columns, the length and uniformity of the pile body can be determined by the detected magnetic field. Compared with the destructive drilling method and the ultrasonic detection of pile length, the detection speed is faster, and is not affected by groundwater and loose soil layers. It can be applicable to various geological conditions such as sand layers and clay.

[0069] While the present invention has been disclosed above with reference to preferred embodiments, this is not intended to limit the present invention. Persons skilled in the art will readily appreciate that various modifications and variations can be made without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be determined by the claims.

Claims

1. An alternating grouting cement jet grouting pile construction device, characterized in that: include: A drilling rig platform (200) is provided with a drill rod (210), a shotcrete mixing head (220) is provided at the bottom of the drill rod (210), a first nozzle and a second nozzle are provided on the surface of the shotcrete mixing head (220), a first channel connected to the first nozzle and a second channel connected to the second nozzle are provided in the drill rod (210), and the drilling rig platform (200) is used to drive the drill rod (210) to rotate at a predetermined speed and feed along its axial direction, so that the shotcrete mixing head (220) is drilled from the surface to a target depth; A slurry supply component comprises a first slurry mixing chamber (310) and a second slurry mixing chamber (320), wherein the first slurry mixing chamber (310) is used to store a first slurry, and the second slurry mixing chamber (320) is used to store a second slurry, and the outlet of the first slurry mixing chamber (310) is provided with a first mud pump (311), and the first mud pump (311) is used to transport the first slurry to the first channel inlet of the drill pipe (210); and the outlet of the second slurry mixing chamber (320) is provided with a second mud pump (312), and the second mud pump (312) is used to transport the second slurry to the second channel inlet of the drill pipe (210); The first slurry comprises a mixed slurry of cement and water, and the second slurry comprises a mixed slurry of cement, iron powder and water; During the process of lifting the drill rod (210) from the target depth to the surface, the first mud pump (311) and the second mud pump (312) alternately provide the first slurry and the second slurry to the drill rod (210), and the spraying mixing head (220) alternately sprays the first slurry and the second slurry during the upward lifting process, so that the formed jet grouting pile (100) includes alternately distributed first columns (102) and second columns (101), wherein the second columns (101) contain iron powder.

2. The alternate grouting type cement jet grouting pile construction device according to claim 1, characterized in that: The output pressure of the second mud pump (312) is P2, and the output pressure of the first mud pump (311) is P1, wherein P2=105% to 110% of P1.

3. The alternate grouting type cement jet grouting pile construction device according to claim 1, characterized in that: The start and stop times of the first mud pump (311) and the second mud pump (312) are set to be related to the drilling depth of the drill rod (210). When the drill rod (210) is in the depth range of the first column (102), the first mud pump (311) remains in an open state and the second mud pump (312) remains in a closed state. When the drill rod (210) is in the depth range of the second pile body (101), the second mud pump (312) remains in an open state and the first mud pump (311) remains in a closed state.

4. The alternate grouting type cement jet grouting pile construction device according to claim 1, characterized in that: The first nozzle and the second nozzle on the surface of the spraying mixing head (220) are located at the same horizontal height.

5. The alternate grouting type cement jet grouting pile construction device according to claim 1, characterized in that: The height ratio of the first column (102) to the second column (101) is 8:2 to 9:1, and the thickness of the second column (101) is at least 10 cm.

6. A magnetic marker pile length detection method, characterized in that: The following steps are involved: Step 1: Using the alternate grouting cement jet grouting pile construction device according to any one of claims 1 to 5 to construct a jet grouting pile (100); Step 2: arranging at least one magnetoresistive sensor (400) above the jet-jet pile (100); Step 3: starting the magnetoresistive sensor (400) to collect the magnetic field intensity B of the jet grouting pile (100); Step 4: Perform peak detection and marking on the magnetic field intensity B collected by the magnetoresistive sensor (400), determine the number and position of the marking areas, define the nearest marking area as A1, and the farthest marking area as A k (k=1,2,3...,n); Step 5: Calculate the length of the jet grouting pile (100) according to the number of marking areas and the distance between adjacent marking areas.

7. The magnetic marker pile length detection method according to claim 6, characterized in that: In step 2, a plurality of magnetoresistive sensors (400) are provided, wherein the plurality of magnetoresistive sensors (400) are distributed in a ring shape around the axis of the jet grouting pile (100); Each magnetoresistive sensor (400) is numbered C1, C2, C3...Cn.

8. The magnetic marker pile length detection method according to claim 7, characterized in that: In step 3, all magnetoresistive sensors (400) are turned on synchronously. In step 4, the magnetic field strength B collected by each magnetoresistive sensor (400) is i (i=1, 2, 3..., n) to perform peak detection and marking, and evaluate the uniformity of the pile body based on the magnetic field intensity data collected by different magnetoresistive sensors (400) in the same marking area.

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