CN110629738A - Device for eliminating influence of dowel bar weight on accuracy of spiral plate load test - Google Patents

Device for eliminating influence of dowel bar weight on accuracy of spiral plate load test Download PDF

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Publication number
CN110629738A
CN110629738A CN201910938641.4A CN201910938641A CN110629738A CN 110629738 A CN110629738 A CN 110629738A CN 201910938641 A CN201910938641 A CN 201910938641A CN 110629738 A CN110629738 A CN 110629738A
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CN
China
Prior art keywords
hollow dowel
dowel bar
hollow
sleeve
accuracy
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Pending
Application number
CN201910938641.4A
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Chinese (zh)
Inventor
陈则连
陈新军
司鹏飞
李国和
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China Railway Design Corp
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China Railway Design Corp
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Publication date
Application filed by China Railway Design Corp filed Critical China Railway Design Corp
Priority to CN201910938641.4A priority Critical patent/CN110629738A/en
Publication of CN110629738A publication Critical patent/CN110629738A/en
Pending legal-status Critical Current

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    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
    • E02D1/00—Investigation of foundation soil in situ
    • E02D1/02—Investigation of foundation soil in situ before construction work
    • E02D1/022—Investigation of foundation soil in situ before construction work by investigating mechanical properties of the soil
    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
    • E02D2600/00—Miscellaneous
    • E02D2600/10—Miscellaneous comprising sensor means

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  • Engineering & Computer Science (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Mining & Mineral Resources (AREA)
  • Soil Sciences (AREA)
  • Analytical Chemistry (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • Chemical & Material Sciences (AREA)
  • Paleontology (AREA)
  • Civil Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Structural Engineering (AREA)
  • Investigating Strength Of Materials By Application Of Mechanical Stress (AREA)
  • Investigation Of Foundation Soil And Reinforcement Of Foundation Soil By Compacting Or Drainage (AREA)

Abstract

The invention relates to a device for eliminating the influence of the weight of a dowel bar on the accuracy of a spiral plate load test, which balances the friction force with the gravity generated by the weight of a hollow dowel bar and a hollow dowel shaft through the adjustable friction force of a friction pipe, blocks the downward movement of the hollow dowel bar and the hollow dowel shaft, eliminates the load of the hollow dowel bar connection combination and the weight of the hollow dowel shaft on a spiral bearing plate, and obviously improves the accuracy of the spiral plate load test.

Description

Device for eliminating influence of dowel bar weight on accuracy of spiral plate load test
Technical Field
The invention belongs to spiral plate load test equipment, and particularly relates to a device for eliminating influence of the weight of a dowel bar on the accuracy of a spiral plate load test.
Background
Patent No. CN201610061487.3 entitled "method for eliminating influence of dowel bar bending on accuracy of spiral plate load test and displacement detector thereof" discloses a spiral plate load test method, the method discloses a structure which comprises a reaction frame, an oil jack, a hollow dowel bar connecting combination, a sleeve connecting combination, a load pressure detector, a linear type capacitive grid displacement sensor, a capacitive grid displacement sensor shell formed by connecting a sleeve joint, a transmission joint and a seal head in a threaded manner, the device comprises a hollow dowel shaft connected with a transmission joint spline, a pressure spring for absorbing vibration and impact energy, a load pressure detector, a spiral bearing plate, a reference beam, a sleeve chuck, a load pressure detector, a linear capacitance grid displacement sensor signal cable and a measurement data recorder, wherein the load pressure detector and the spiral bearing plate are sequentially connected with the hollow dowel shaft, the reference beam is used for testing a hole position orifice, the sleeve chuck is fixed on the reference beam, and the load pressure detector and the linear capacitance grid displacement sensor signal cable are led out from the hollow dowel rod.
According to the method, the linear capacitive grating displacement detector for detecting the sinking displacement of the spiral bearing plate is arranged underground, namely the lowest end of the hollow dowel bar connecting combination, so that the problem that the bending of the dowel bar influences the accuracy of a spiral plate load test can be completely solved.
Before the operation of the spiral plate load test equipment, the load pressure displayed by the measuring data recorder is firstly cleared, and the load pressure displayed at the moment is generally considered to be a pressure value generated by the rotary penetration of the spiral bearing plate. Research shows that a certain load exists on the spiral bearing plate due to the weight of the hollow dowel bar connecting combination and the hollow dowel shaft, the pressure applied to the spiral bearing plate can be converted according to the load, and the pressure inevitably causes the foundation soil to sink, so that the load component existing in the weight of the hollow dowel bar connecting combination and the hollow dowel shaft is neglected by 'zero clearing' of the load pressure displayed by the measurement data recorder before operation, and the accuracy of a spiral plate load test is inevitably influenced.
Disclosure of Invention
The invention discloses a device for eliminating the influence of the weight of a dowel bar on the accuracy of a spiral plate load test in order to improve the accuracy of the spiral plate load test.
The invention adopts the following technical scheme for realizing the purpose: the utility model provides an eliminate device that dowel bar weight influences spiral plate load test accuracy, includes reaction frame, hydraulic jack, hollow dowel bar connection combination, bushing assembly, load pressure detector and linear type grid displacement sensor, bushing joint, transmission joint and head threaded connection constitute grid displacement sensor casing, hollow dowel bar with transmission joint splined connection and its pressure spring that absorbs vibration and impact energy connect gradually in the load pressure detector of hollow dowel barThe device comprises a spiral bearing plate, a reference beam for testing an orifice of a hole position, a sleeve chuck fixed on the reference beam, a load pressure detector and a linear type capacitive grating displacement sensor signal cable which are led out from a hollow dowel bar, and a measurement data recorder connected with the signal cable, and is characterized in that two half tiles which are provided with convex edges and are butted are arranged in the end port of a sleeve fastened on the sleeve chuck, the convex edges of the two half tiles are supported on the end edge of the sleeve, the butted two half tiles are supported with a friction pipe the inner wall of which is jointed with the hollow dowel bar,:the friction tube being provided with means for elastically deforming it:The axial leads to the groove, the friction pipe is equipped with the clamp of frictional force between adjustment it and the hollow dowel bar, the gravity that frictional force and hollow dowel bar and hollow dowel shaft weight produced is balanced mutually.
The invention can also adopt the following technical measures:
:the friction pipe is made of nylon.
The invention has the advantages that: the friction force adjustable by the friction pipe is balanced with the gravity generated by the weight of the hollow dowel bar and the hollow dowel shaft, so that the downward movement of the hollow dowel bar and the hollow dowel shaft is blocked, the load of the hollow dowel bar connection combination and the weight of the hollow dowel shaft on the spiral bearing plate is eliminated, and the accuracy of a spiral plate load test is obviously improved.
Drawings
FIG. 1 is a schematic structural diagram of an embodiment of the device.
Fig. 2 is an enlarged cross-sectional view of fig. 1A-a.
FIG. 3 is an enlarged cross-sectional view of the sleeve and half-tile structure of FIG. 1.
Fig. 4 is an enlarged cross-sectional view of the hollow power transmission shaft and related components shown in fig. 1.
The labels in the figure are: 1 reaction frame, 2 hydraulic jack, 3 hollow dowel bar connection combination, 4 friction tube, 4-1:The device comprises an axial through groove, a 5-hoop, 6 half-tile, 7-sleeve chuck, 8-datum beam, 9-sleeve connecting combination, 10-sleeve joint, 11-transmission joint, 12-end socket, 13-hollow force transmission shaft, 14-load pressure detector and 15-spiral connectorThe pressure bearing plate, 16 signal cables, 17 wire passing flange plates, 18 linear type capacitive grating displacement sensors and 19 pressure springs.
Detailed Description
The invention is further illustrated by the following examples and figures.
As shown in figures 1 and 4, the invention is an improvement on the structure basis of a method for eliminating the influence of the bending of a dowel bar on the accuracy of a spiral plate load test and a displacement detector thereof in the patent number CN201610061487.3, and the disclosed structure comprises a reaction frame 1, an oil jack 2, a hollow dowel bar connecting combination 3, a sleeve connecting combination 9, a load pressure detector 14, a linear capacitance grid displacement sensor 18, a sleeve joint 10, a transmission joint 11 and a seal head 12 which are in threaded connection to form a linear capacitance grid displacement sensor shell, a hollow dowel shaft 13 in splined connection with the transmission joint 11, a pressure spring 19 which is used for absorbing vibration and impact energy and acts on the hollow dowel shaft, and the load pressure detector 14 and the spiral pressure bearing plate 15 which are sequentially connected with the hollow dowel shaft 13.
The device also comprises a reference beam 8 for testing the hole position orifice, a sleeve chuck 7 fixed on the reference beam, a load pressure detector led out from a wire passing flange 17 at the upper end of the hollow dowel bar 13 and a signal cable 16 of the linear capacitive grating displacement sensor, and a measurement data recorder (not shown) connected with the ground.
In fig. 1, the rotary pressurizing device for the casing joint assembly 9 is a drilling machine, and the loading device for the hollow dowel bar joint assembly 3 is an oil jack 2.
As shown in fig. 1, 2 and 3, the end of the sleeve fastened to the sleeve chuck 7 is provided with two half-tiles 6 which are provided with convex edges and butted, the convex edges of the two half-tiles are supported on the end edge of the sleeve, the butted two half-tiles are supported with a friction tube 4 the inner wall of which is jointed with the hollow dowel bar,:the friction tube being provided with means for elastically deforming it:The axial through groove 4-1, the friction pipe 4 is provided with a hoop 5 for adjusting the friction force between the friction pipe and the hollow dowel bar, and the friction force is adjusted to balance with the gravity generated by the hollow dowel bar and the hollow dowel shaft.
The friction pipe 4 of the embodiment is a friction pipe made of nylon.
The operation and adjustment steps of the present invention are described below in conjunction with fig. 1 and 4:
1. drilling at a set hole position by a drilling machine, and stopping drilling at a position 1 m away from the test hole;
2. the lower end of the hollow dowel shaft 13 is sequentially connected with a load pressure detector 14 and a spiral bearing plate 15, the hollow dowel bar is connected to the upper end of the hollow dowel shaft 13, and a signal cable 16 is led out from a wire passing flange 17 at the upper end of the hollow dowel bar;
3. sleeving a sleeve outside the hollow dowel bar, connecting the sleeve with a sleeve joint 10, and connecting the upper end of the sleeve with a drilling machine;
4. and starting a drilling machine to rotatably penetrate the sleeve into the test hole site, wherein the penetration amount of one rotation of the sleeve is equal to the thread pitch of the spiral bearing plate 15. Then, increasing the hollow dowel bars and the sleeves section by section to respectively form a hollow dowel bar connecting combination 3 and a sleeve pipe connecting combination 9, and leading out the signal cables 16 from the hollow dowel bars increased each time;
5. stopping drilling when the spiral bearing plate 15 reaches a set depth, removing the drilling machine, arranging a reference beam 8 which is supported on the ground and fixed by a ground anchor and is provided with a casing chuck 7, fastening a second section of casing by the casing chuck 7, dismantling a first section of casing, and arranging a reaction frame 1 which is connected and combined corresponding to the hollow dowel bar;
6. two half tiles 6 are placed in the upper port of the second section of sleeve, the two half tiles are butted and the convex edges of the two half tiles are supported at the end edge of the sleeve, a friction pipe 4 and a clamp 5, the inner wall of which is jointed with the hollow dowel bar, are arranged on the two butted half tiles, and the clamp is screwed to avoid the hollow dowel bar from falling down;
7.:connecting a signal cable 16 to a measurement data recorder, installing a probe rod extractor, unscrewing a hoop, lifting a hollow dowel bar by the probe rod extractor while observing pressure reading so that the pressure reading of the measurement data recorder is zero', adjusting the hoop to increase the friction force of a friction tube 4 towards the screwing direction, and keeping the pressure reading in a zero state, wherein the friction force of the friction tube 4 is balanced with the gravity generated by the weight of the hollow dowel bar and the weight of a hollow dowel shaft, the lifting distance of the hollow dowel bar is micro, and a pressure spring 17 sleeved on the hollow dowel shaft 13 is convenient for adjusting the pressure reading to be zero;
8. the oil jack 2 between the reaction frame 1 and the hollow dowel bar connecting combination 3 is used for loading the hollow dowel bar in a grading way according to the standard requirements of a sedimentation relative stability method or an equal sedimentation rate method until the test is finished.
The following examples illustrate the application effects of the present invention:
in the spiral plate load test of 10 m and 12 m depth of the Tianjin subway project, the following verification test is carried out:
1. 10 m depth test without using a friction tube: before the test is started, a signal wire of the probe assembly is connected with a data recorder on the ground, and the load reading of the data recorder is reset to zero. When the spiral bearing plate reaches the depth of 10 meters, the sleeve is fixed by the sleeve chuck, the signal cable is connected with a data recorder, and the record reading is 84.7 kPa.
12 m depth test without friction tube: before the test is started, a signal wire of the probe assembly is connected with a data recorder on the ground, and the load reading of the data recorder is reset to zero. When the spiral bearing plate reaches the depth of 12 meters, the sleeve is fixed by the sleeve chuck, the signal cable is connected with the data recorder, and the record reading is 99.6kPa at the moment.
And (3) analysis: the recorded readings of 84.7kPa and 99.6kPa during the test are the deadweights of the hollow dowel bars and the hollow dowel shafts during the test of 10 meters and 12 meters respectively, the reading is increased along with the increase of the test depth, and the reading is increased along with the increase of the number of the hollow dowel bars. Meanwhile, the self weights of the hollow dowel bars and the hollow dowel shafts generate pressure on the tested soil body, so that the soil body is compressed to a certain extent before the test is started, the soil body is in an ex-situ stress state, and the test result cannot reflect the actual situation of the in-situ soil body.
2. 10 m depth test using friction tube: after the spiral bearing plate reaches 10 meters of depth, it is fixed with the sleeve pipe with the sleeve chuck, install two half tiles, hug closely two half tile upper portions installation friction tube and clamp, connect the signal cable in measured data record appearance, installation probe rod extractor, the loose clamp is unscrewed, promote hollow dowel steel through probe rod extractor when observing pressure reading and make the pressure reading of measured data record appearance be 'zero', adjust the clamp towards the direction of screwing and increase the frictional force of friction tube, can carry out the spiral plate load test after the reading that makes the record appearance keeps to 0 kPa.
And (3) analysis: after the friction pipe is used, the friction force is offset by adjusting the whole friction force between the friction pipe and the hollow dowel bar before the test is started, the dead weight of the hollow dowel bar and the dead weight of the hollow dowel shaft are offset, when the test depth is reached, the dead weight of the hollow dowel bar cannot generate pressure on the soil body, the soil body is in an in-situ stress state, and the accuracy of a spiral plate load test result is ensured.

Claims (2)

1. Eliminate device of dowel steel weight influence spiral plate load test accuracy, including reaction frame, hydraulic jack, hollow dowel steel linkage, bushing assembly, load pressure detector and linear type capacitance grid displacement sensor, casing joint, transmission joint and head threaded connection constitute the appearance grid displacement sensor casing, hollow dowel steel that connects the spline connection with the transmission and its absorb vibration and impact energy's pressure spring, connect gradually in the load pressure detector and the spiral bearing plate of hollow dowel steel, the reference beam in experimental hole site drill way, the casing chuck that is fixed in the reference beam, the load pressure detector and the linear type capacitance grid displacement sensor signal cable of drawing forth from hollow dowel steel, connect the measured data record appearance of signal cable, its characterized in that: the end opening of the sleeve fastened on the sleeve chuck is provided with two half-tiles which are provided with convex edges and are butted, the convex edges of the two half-tiles are supported on the end edge of the sleeve, the butted two half-tiles are supported with a friction pipe the inner wall of which is jointed with the hollow dowel bar,:the friction tube being provided with means for elastically deforming it:The axial leads to the groove, the friction pipe is equipped with the clamp of frictional force between adjustment it and the hollow dowel bar, the gravity that frictional force and hollow dowel bar and hollow dowel shaft weight produced is balanced mutually.
2. The device for eliminating the influence of the weight of the dowel bar on the accuracy of the spiral plate load test according to claim 1, wherein the device comprises: the friction pipe is made of nylon.
CN201910938641.4A 2019-09-30 2019-09-30 Device for eliminating influence of dowel bar weight on accuracy of spiral plate load test Pending CN110629738A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN201910938641.4A CN110629738A (en) 2019-09-30 2019-09-30 Device for eliminating influence of dowel bar weight on accuracy of spiral plate load test

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN201910938641.4A CN110629738A (en) 2019-09-30 2019-09-30 Device for eliminating influence of dowel bar weight on accuracy of spiral plate load test

Publications (1)

Publication Number Publication Date
CN110629738A true CN110629738A (en) 2019-12-31

Family

ID=68973813

Family Applications (1)

Application Number Title Priority Date Filing Date
CN201910938641.4A Pending CN110629738A (en) 2019-09-30 2019-09-30 Device for eliminating influence of dowel bar weight on accuracy of spiral plate load test

Country Status (1)

Country Link
CN (1) CN110629738A (en)

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