Device and method for detecting sediment thickness at bottom of bored pile hole

Abstract

The present invention discloses a device and method for detecting the thickness of sediment at the bottom of a bored pile hole. The measuring cake of the device is provided with a through hole, a measuring needle positioning sleeve is provided on the top surface of the measuring cake and is coaxial with the through hole, long grooves are provided on both sides of the measuring needle positioning sleeve, and the measuring needle is inserted into the measuring needle positioning sleeve. The left and right brackets are provided on the top surface of the measuring cake and are located on both sides of the measuring needle positioning sleeve. Two L-shaped lock buckles are hinged to the left and right brackets and the short arms are directly opposite to the long grooves of the measuring needle positioning sleeve. A wire collection ring is provided at the top of the measuring needle. Two pull ropes pass through the wire collection ring and the bottom ends are connected to the long arm free ends of the two L-shaped lock buckles, and the top ends pass through the wire collection ring and then merge into a pull rope. The method locks the measuring needle position through the two L-shaped lock buckles, releases the locking of the measuring needle when the measuring cake is placed on the surface of the sediment at the bottom of the hole, and the measuring needle passes through the through hole of the measuring cake and is inserted down to the bottom of the hole; after the measuring needle position is locked again, the measuring cake and the measuring needle are lifted out by the pull rope, and the length of the measuring needle protruding is measured as the sediment thickness. The device and method can accurately measure the sediment thickness at the bottom of the hole and significantly improve the efficiency of the detection operation.

Description

Technical Field

[0001] The invention relates to the technical field of construction engineering, and in particular to a device and method for detecting the thickness of sediment at the bottom of a bored pile hole. Background Art

[0002] The sediment at the bottom of the bored pile hole refers to the sediment left by the precipitated or collapsed hole during the drilling and emptying process, which is not carried away by the circulating mud. It is generally coarse particles, and the sediment thickness is the sediment layer height. The existence of sediment greatly affects the compressive bearing capacity of the concrete bored pile, or makes the settlement of the building exceed the design requirements. Therefore, the construction and inspection specifications of bored piles have strict regulations on the thickness of sediment. Generally, the sediment thickness should not exceed 50-200mm, and the inspection accuracy is less than 10mm.

[0003] At present, the methods for detecting the thickness of sediment at the bottom of bored pile holes are basically divided into two categories: resistivity difference method and hammer method (including similar cone method, cake method, needle method, etc.).

[0004] The resistivity difference method uses a measuring probe to measure the resistivity around the probe when the probe is lowered to the bottom of the hole in the mud of the pile hole. The resistivity of the sediment is different from that of the mud. By measuring the change in resistivity at the bottom of the hole, the thickness of the sediment can be measured. Generally, two electrodes are installed at the lower end of the probe. When the electrodes are buried in the sediment, the resistivity of the surrounding materials can be measured by powering on. When the probe lifts the sediment out of the mud, the resistivity of the mud can be measured. The thickness of the sediment can be measured from the resistivity change curve. The probe is connected to the host, and the host sends a command to collect the resistivity. The resistivity at different depths of the bottom of the hole is measured to obtain the thickness of the sediment at the bottom of the hole.

[0005] The hammer method, cone method, and cake and needle method are different. The hammer method uses a measuring rope to put the hammer to the bottom of the hole, and then feel the top of the sediment by hand. Then, according to the hole depth measured during drilling, the depth from the top of the sediment to the hole mouth is subtracted to get the sediment thickness. Its measurement accuracy is limited. The cake and needle method measures the top of the sediment with a cake, and measures the position from the cake to the bottom of the hole with a needle. The sediment thickness is obtained by subtracting the depth of the two. The measured pile hole depth can be tens to hundreds of meters. Since it is measured twice and the distance is measured with a measuring rope, it is affected by the tension of the measuring rope and the cumulative error of the two measurements. The final sediment thickness measurement accuracy is limited, and the measurement time is relatively long.

[0006] In order to improve the detection accuracy of the cake-and-needle method, at present, an electromechanical device is used to combine the cake and the needle. After the cake reaches the top of the sediment, the upper host sends a command to press the needle into the sediment through the power device, and then automatically measures the penetration depth of the needle, that is, the sediment thickness. This detection method has a clear principle and accurate measurement, but it requires a set of electromechanical devices and control systems, the equipment cost is high, the operation is cumbersome, and the detection efficiency is not high. Summary of the invention

[0007] The technical problem to be solved by the present invention is a device and method for detecting the thickness of the sediment at the bottom of a bored pile hole. The device and method overcome the defects of traditional detection of the sediment thickness at the bottom of the hole. The device has a simple structure, is easy to manufacture, and has extremely low cost. The method is easy to operate, can accurately measure the sediment thickness at the bottom of the hole, and significantly improves the efficiency of the detection operation.

[0008] In order to solve the above technical problems, the detection device for the sediment thickness at the bottom of the bored pile hole of the present invention comprises a measuring cake, a measuring needle, a measuring needle positioning sleeve, a left bracket, a right bracket, a wire gathering ring, two L-shaped lock buckles and two pull ropes, the measuring cake is provided with a through hole in the center, the measuring needle positioning sleeve is arranged on the top surface of the measuring cake and is coaxial with the through hole, long grooves are arranged on both sides of the measuring needle positioning sleeve along the length direction, the measuring needle is inserted into the measuring needle positioning sleeve, the left bracket and the right bracket are respectively arranged on the top surface of the measuring cake and are located on both sides of the measuring needle positioning sleeve, the long arms and short arms of the two L-shaped lock buckles are respectively hinged to the left bracket and the right bracket at the junction, and the short arms are opposite to the long grooves on both sides of the measuring needle positioning sleeve, the wire gathering ring is arranged at the top end of the measuring needle, the two pull ropes pass through the wire gathering ring and the bottom ends are respectively connected to the free ends of the long arms of the two L-shaped lock buckles, and the top ends pass through the wire gathering ring and merge into one pull rope.

[0009] Furthermore, the measuring cake is a steel plate with a thickness of 5 mm and a diameter of 200 mm, and the measuring needle is a round steel bar with a diameter of Φ10-25 mm and a length of 200 mm.

[0010] Furthermore, the outer diameter of the wire collection ring is greater than the inner diameter of the measuring needle positioning sleeve.

[0011] Furthermore, the device also includes a counterweight block, which is arranged at the top of the measuring needle and below the line collection ring.

[0012] Furthermore, the surface of the lower section of the measuring needle is provided with threaded rings at intervals along the axial direction.

[0013] A method for detecting the thickness of sediment at the bottom of a bored pile hole based on the above device comprises the following steps:

[0014] Step 1: Before putting the device into the pile hole, place it on a flat surface so that the bottom of the probe is flush with the bottom of the test cake;

[0015] Step 2: Pull up a pull rope above the cable collection ring, and the two L-shaped lock buckles rotate along the hinge points with the left bracket and the right bracket respectively, so that the short arms of the two L-shaped lock buckles extend into the long grooves on the two sides of the stylus positioning sleeve and press against the stylus, locking the position of the stylus in the stylus positioning sleeve;

[0016] Step 3: Lift the pull rope and put the device into the pile hole. When the test cake is on the surface of the sediment at the bottom of the hole, the sediment will support the test cake. Release the pull rope, and at the same time, the two L-shaped locks will reset and release the lock on the measuring needle. The measuring needle will pass through the central through hole of the test cake and go down to the bottom of the hole.

[0017] Step 4. Lift the pull rope again, and the two L-shaped locks lock the position of the measuring needle. Then use the pull rope to pull the device out of the pile hole. The length of the measuring needle protruding from the bottom of the measuring cake is the sediment thickness.

[0018] Since the device and method for detecting the thickness of sediment at the bottom of bored pile holes of the present invention adopt the above-mentioned technical scheme, that is, a through hole is provided at the center of the measuring cake of the device, a measuring needle positioning sleeve is provided on the top surface of the measuring cake and is coaxial with the through hole, long grooves are provided on both sides of the measuring needle positioning sleeve, the measuring needle is inserted into the measuring needle positioning sleeve, the left and right brackets are provided on the top surface of the measuring cake and are located on both sides of the measuring needle positioning sleeve, two L-shaped lock buckles are hinged to the left and right brackets and the short arms are directly opposite to the long grooves on both sides of the measuring needle positioning sleeve, the wire collection ring is fixed to the top of the measuring needle, two pull ropes pass through the wire collection ring and are connected to the long arm free ends of the two L-shaped lock buckles at the bottom, and the top passes through the wire collection ring and then merges into a pull rope. The method locks the measuring needle position through two L-shaped lock buckles, releases the measuring needle lock when the measuring cake is placed on the sediment surface at the bottom of the hole, and the measuring needle passes through the central through hole of the measuring cake and is inserted down to the bottom of the hole; when the pull rope is pulled upward, the measuring needle position is locked again and the measuring cake and the measuring needle are lifted out, and the length of the measuring needle protruding is measured as the sediment thickness. The device has a simple structure, is easy to manufacture, and has extremely low cost; the method is easy to operate, can accurately measure the thickness of the sediment at the bottom of the hole, and significantly improves the efficiency of the detection operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The present invention is further described in detail below in conjunction with the accompanying drawings and embodiments:

[0020] Figure 1 It is a schematic diagram of the structure of a device for detecting the thickness of sediment at the bottom of a bored pile hole according to the present invention;

[0021] Figure 2 This is a schematic diagram of the locking state of the measuring needle position in the detection device;

[0022] Figure 3 This is a schematic diagram of the detection device being located on the sediment surface at the bottom of the bored pile hole to detect sediment thickness;

[0023] Figure 4 This is a schematic diagram of the bored pile hole proposed by using a pull rope for this detection device. DETAILED DESCRIPTION

[0024] Implementation example Figure 1 and Figure 2As shown, the device for detecting the sediment thickness at the bottom of the bored pile hole of the present invention comprises a measuring cake 11, a measuring needle 12, a measuring needle positioning sleeve 2, a left bracket 3, a right bracket 4, a wire collection ring 5, two L-shaped lock buckles 8 and two pull ropes 9. The measuring cake 11 is provided with a through hole in the center, the measuring needle positioning sleeve 2 is provided on the top surface of the measuring cake 11 and is coaxial with the through hole, long grooves 21 are provided on both sides of the measuring needle positioning sleeve 2 along the length direction, the measuring needle 12 is inserted into the measuring needle positioning sleeve 2, and the left bracket 3 and the right bracket 4 are respectively provided at The top surface of the measuring disc 11 is located on both sides of the measuring needle positioning sleeve 2. The long arms 81 and short arms 82 of the two L-shaped locking buckles 8 are respectively hinged to the left bracket 3 and the right bracket 4 at their junctions, and the short arms 82 are opposite to the long grooves 21 on both sides of the measuring needle positioning sleeve 2. The wire gathering ring 5 is arranged at the top of the measuring needle 12. The two pull ropes 9 pass through the wire gathering ring 5 and the bottom ends are respectively connected to the free ends of the long arms 81 of the two L-shaped locking buckles 8, and the top ends pass through the wire gathering ring 5 and then merge into a pull rope 91.

[0025] Preferably, the measuring cake 11 is a steel plate with a thickness of 5 mm and a diameter of 200 mm, and the measuring needle 12 is a round steel bar with a diameter of Φ10-25 mm and a length of 200 mm.

[0026] Preferably, the outer diameter of the cable ring 5 is larger than the inner diameter of the probe positioning sleeve 2. The pull rope passes through the cable ring to keep the entire detection device vertical. At the same time, if the probe falls out of the test cake, it is still connected to the pull rope through the cable ring and will not fall.

[0027] Preferably, the device further comprises a counterweight 6, which is arranged at the top of the measuring needle 12 and below the line collection ring 5. The counterweight can be set according to the nature of the sediment. During the drilling process, the sediment is formed by the sand particles of the mud in the hole settling to the bottom of the hole. It is a loose accumulation mixed with mud and clay. The sediment can be easily inserted into the sediment using a conventional measuring needle; however, for sediment containing large particles of sand and gravel in some areas, the counterweight can ensure that the measuring needle is inserted into the sediment.

[0028] Preferably, the lower surface of the measuring needle 12 is provided with threaded circles 7 at intervals along the axial direction. When the short arms of the two L-shaped lock buckles are extended into the long grooves on the two sides of the measuring needle positioning sleeve and pressed against the measuring needle by pulling the rope, the short arms of the L-shaped lock buckles are pressed against the adjacent threaded circles, thereby ensuring that the L-shaped lock buckles clamp the measuring needle and avoid relative sliding between the two, especially for the measuring needle with a counterweight block, the locking of the measuring needle can be ensured. At the same time, the detection accuracy of the sediment thickness is required to be less than 10mm, and the spacing between adjacent threaded circles is much less than 10mm, so the threaded circles on the measuring needle surface do not affect the detection accuracy of the device.

[0029] like Figure 3 and Figure 4As shown, a method for detecting the thickness of sediment at the bottom of a bored pile hole based on the above device comprises the following steps:

[0030] Step 1: Before inserting the device into the pile hole 10, place the device on a flat surface so that the bottom end of the measuring needle 12 is flush with the bottom surface of the measuring cake 11;

[0031] Step 2: Pull up a pull rope 91 above the wire collection ring 5, and the two L-shaped lock buckles 8 rotate along the hinge points with the left bracket and the right bracket respectively, so that the short arms of the two L-shaped lock buckles 8 extend into the long grooves on the two sides of the measuring needle positioning sleeve 2 and press against the measuring needle 12, locking the position of the measuring needle 12 in the measuring needle positioning sleeve 2; when the rope is lifted to move the device, the measuring needle and the measuring cake are locked together and will not move relative to each other

[0032] Step 3: lift the pull rope 91 and put the device into the pile hole 10. When the test cake 11 is located on the surface of the sediment 13 at the bottom of the hole, the test cake 11 is supported by the sediment 13. Release the pull rope 91, and at the same time, the two L-shaped lock buckles 8 are reset and the lock on the measuring needle 12 is released. The measuring needle 12 passes through the central through hole of the test cake 11 and is inserted into the bottom of the hole.

[0033] Step 4: lift the pull rope 91 again, the two L-shaped lock buckles 8 lock the position of the measuring needle 12, and then pull the device out of the pile hole 10 through the pull rope 91, and measure the length of the measuring needle 12 protruding from the bottom of the measuring cake 11 to obtain the thickness of the sediment 13.

[0034] The device and method utilize the measuring cake and measuring needle method to detect the sediment thickness, but do not require electromechanical devices and control systems. Only a set of automatic locking and unlocking mechanisms are used to lock and unlock the measuring needles, and the sediment thickness can be accurately measured. The device has extremely low manufacturing costs, excellent detection effects, and convenient detection operations, which significantly improves detection operation efficiency.

Claims

1. A device for detecting the thickness of sediment at the bottom of a bored pile hole, comprising a measuring cake and a measuring needle, characterized in that: The device also includes a measuring needle positioning sleeve, a left bracket, a right bracket, a wire gathering ring, two L-shaped locking buckles and two pull ropes, the center of the measuring cake is provided with a through hole, the measuring needle positioning sleeve is arranged on the top surface of the measuring cake and is coaxial with the through hole, long grooves are arranged on both sides of the measuring needle positioning sleeve along the length direction, the measuring needle is inserted into the measuring needle positioning sleeve, the left bracket and the right bracket are respectively arranged on the top surface of the measuring cake and are located on both sides of the measuring needle positioning sleeve, the long arms and short arms of the two L-shaped locking buckles are respectively hinged to the left bracket and the right bracket at the junction, and the short arms are opposite to the long grooves on both sides of the measuring needle positioning sleeve, the wire gathering ring is arranged at the top end of the measuring needle, the two pull ropes pass through the wire gathering ring and the bottom ends are respectively connected to the free ends of the long arms of the two L-shaped locking buckles, and the top ends pass through the wire gathering ring and then merge into a pull rope; the device also includes a counterweight block, the counterweight block is arranged on the top end of the measuring needle and is located below the wire gathering ring, and the surface of the lower section of the measuring needle is provided with threaded rings at intervals along the axial direction.

2. The device for detecting the thickness of sediment at the bottom of a bored pile hole according to claim 1, characterized in that: The measuring cake is a steel plate with a thickness of 5 mm and a diameter of 200 mm, and the measuring needle is a round steel bar with a diameter of Φ10-25 mm and a length of 200 mm.

3. The device for detecting the thickness of sediment at the bottom of a bored pile hole according to claim 1 or 2, characterized in that: The outer diameter of the line collection ring is greater than the inner diameter of the measuring needle positioning sleeve.

4. A method for detecting the thickness of sediment at the bottom of a bored pile hole based on the device according to any one of claims 1 to 3, characterized in that This method comprises the following steps: Step 1: Before putting the device into the pile hole, place it on a flat surface so that the bottom of the probe is flush with the bottom of the test cake; Step 2: Pull up a pull rope above the cable collection ring, and the two L-shaped lock buckles rotate along the hinge points with the left bracket and the right bracket respectively, so that the short arms of the two L-shaped lock buckles extend into the long grooves on the two sides of the stylus positioning sleeve and press against the stylus, locking the position of the stylus in the stylus positioning sleeve; Step 3: Lift the pull rope and put the device into the pile hole. When the test cake is on the surface of the sediment at the bottom of the hole, the sediment will support the test cake. Release the pull rope, and at the same time, the two L-shaped locks will reset and release the lock on the measuring needle. The measuring needle will pass through the central through hole of the test cake and go down to the bottom of the hole. Step 4. Lift the pull rope again, and the two L-shaped locks lock the position of the measuring needle. Then use the pull rope to pull the device out of the pile hole. The length of the measuring needle protruding from the bottom of the measuring cake is the sediment thickness.

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