CN106018102B - Anchor pull-out test system for rammed earth sites - Google Patents

Abstract

The invention discloses a group anchor pulling test system for rammed earth sites, comprising a group anchor anchor mechanism, a loading mechanism and a data acquisition and processing system; the group anchor anchor mechanism comprises a rammed earth box, in which a rammed earth box is rammed The rammed earth layer is provided with a plurality of anchor holes, and the plurality of anchor holes are evenly arranged at equal intervals relative to the central axis of the rammed earth layer; An anchoring slurry is arranged between the holes; the rammed earth box includes a box seat and a plurality of box body units arranged above the box seat and arranged in a vertical direction, and the box body units include four channel steels arranged in a rectangular shape. The two adjacent channel steels are fixedly connected through a locking device; the loading mechanism applies tension to the anchor rod, and monitors the anchoring force, the strain and displacement of the anchor rod through a data acquisition and processing system.

Description

Anchor pull-out test system for rammed earth sites

technical field

The invention belongs to the technical field of anchoring for reinforcement of rammed earth sites in the protection of cultural relics, and particularly relates to a group anchor pulling test system of rammed earth sites.

Background technique

As an important building type in ancient China, the rammed earth site has continued to this day. Due to the serious threat of natural environment factors and human activities for many years, the body and carrier of the rammed earth site have experienced various geological disasters. The most common ones are criss-cross and different sizes. Cracks, cutting the rock and soil mass into many dangerous soil masses of different sizes, especially the cracks parallel to the body of the site cut the soil mass apart, causing toppling and collapse, and causing serious damage to the soil site. Based on the principle of "no change to the original state, minimal intervention, and the use of appropriate protection technology" for cultural relics protection, in the protection and reinforcement of rammed earth sites, the full-length bonded anchor bolt anchoring technology has good concealment, little construction disturbance, and is effective. The advantages of controlling deformation and fissure development and mobilizing the bearing capacity of the soil have become the most effective means of controlling the mechanical stability of rammed earth sites.

The current research results of the single-anchor pull-out test system cannot reflect the stress mechanism of the rammed earth site under the anchoring state of multiple anchors, the average single anchoring force and the empirical anchoring design method. For example, in the design of group anchors in geotechnical engineering, there are clear design methods for bolt length, bolt spacing, bolt margin, and number of bolts, but the existing design methods are not suitable for rammed soil. Ruins. Improper reinforcement design changes the stress distribution of the rammed earth site, causing new damage to the rammed earth site and seriously restricting the scientific anchoring design of the rammed earth site.

For the evaluation of the anchoring effect of rammed earth sites, considering the value of the site, indoor full-scale physical simulation pull-out test is still the most intuitive and reliable test method, but the existing single-anchor pull-out test cannot truly reflect the effect of group anchors. At present, there is no indoor simulation test system for group anchor pull-out test in the field of anchoring and reinforcement research of rammed earth sites, which urgently needs to carry out this blank research and development work. Therefore, it is of great significance to develop an indoor pull-out test system that can be used to study the effect of anchoring group anchoring in rammed earth sites, which is of great significance for the applied research of anchor reinforcement design of rammed earth sites.

SUMMARY OF THE INVENTION

The purpose of the present invention is to overcome the defect that the existing rammed earth site pulling tests are all single-anchor pulling, and provide a group anchor pulling test system for rammed earth sites.

The technical scheme provided by the present invention is:

A group anchor pulling test system for rammed earth sites, including group anchor anchoring mechanism, loading mechanism and data acquisition and processing system;

The group anchor anchoring mechanism includes a rammed earth box, a rammed earth layer is rammed in the rammed earth box, and a plurality of anchor holes are arranged in the rammed earth layer, and the plurality of anchor holes are arranged in a direction relative to the central axis of the rammed earth layer. Evenly arranged at equal intervals; anchor rods are arranged in the anchor holes, and anchoring grout is arranged between the anchor rods and the anchor holes;

The rammed earth box includes a box seat and a plurality of box body units arranged above the box seat and arranged in a vertical direction. The box body unit includes four channel steels arranged in a rectangular shape, and two adjacent channel steels are locked by locking. fixed connection;

The loading mechanism applies tensile force to the bolt, and monitors the anchoring force, the strain and displacement of the bolt through a data acquisition and processing system.

Preferably, the loading mechanism includes:

The loading plate is provided with openings, through which the loading plate and the anchor rod are fixed;

a dowel rod, the lower end of which is connected with the middle of the loading plate through a universal joint; the dowel rod is circumferentially arranged with threads;

a reaction force frame, the upper end of the dowel rod passes through the reaction force frame;

a hydraulic oil cylinder, which is arranged on the reaction force frame and makes the dowel rod pass through the hydraulic oil cylinder;

a hand-held rotary anchor head, which is arranged above the hydraulic oil cylinder, and the hand-held rotary anchor head is matched with the thread on the dowel rod to lock the dowel rod;

An oil pump, which is connected with the hydraulic cylinder, provides pressure for the hydraulic cylinder.

Preferably, the reaction force frame includes two vertical beams arranged in parallel, a plurality of fixing plates are arranged on the upper part of the vertical beams from top to bottom, and the horizontal beams are placed on the left and right fixed plates and keep the horizontal beams.

Preferably, the lower end of the vertical beam is provided with a corner brace, and the bottom of the vertical beam is also provided with an automatic leveling support and a moving wheel.

Preferably, the data acquisition and processing system includes:

Strain gauges, which are attached to the bolt to measure the strain of the bolt;

A stress sensor, which is arranged between the hydraulic cylinder and the hand-held rotating anchor head, to measure the anchoring force;

A displacement measuring device, which includes a magnetic watch seat adsorbed on the surface of the outer column of the stress sensor, and a displacement sensor fixed on the beam and connected with the magnetic watch seat to measure the displacement of the anchor rod;

a digital display connected to the stress sensor and the displacement sensor;

a strain acquisition instrument connected to the strain gauge;

a data processor, which is connected with the digital display instrument and the strain acquisition instrument.

Preferably, the bottom of the rammed earth box is provided with an automatic leveling support.

Preferably, there are 2-4 anchor holes.

Preferably, the anchor rod is one of a wooden anchor rod, a bamboo anchor rod, a bamboo reinforced composite anchor rod and a glass fiber anchor rod.

Preferably, the oil pump is a manual oil pump.

Preferably, the axes of the rammed earth layer, the loading plate, the dowel rod, the hydraulic cylinder and the stress sensor are arranged coaxially.

The beneficial effects of the present invention are embodied in the following aspects:

(1) All instruments and accessories are made of steel, which can meet the stiffness requirements of all bolt pull-out tests currently used for anchoring and strengthening of rammed earth sites.

(2) The reaction force frame is a detachable device, and the height and span of the beam can be adjusted through the beam support, which can meet the pulling problem of anchor rods of different lengths.

(3) The rammed earth box is a detachable device, each layer is spliced with four channel steels, which are locked by locking devices, and can be rammed in layers to solve the superimposed ramming process of ancient rammed earth buildings; channel steel can be increased or decreased as required different number of rammed layers to meet the problem of different anchoring depths.

(4) Ribs are set on the upper surface of the loading plate to ensure the stiffness and strength of the loading plate during the pull-out test; the loading plate is divided into a 4-hole loading plate and a 3-hole loading plate, which can meet the requirements of 2, 3, and 4 bolts at the same time. Pulled group anchor problem; the hole is from the center of the loading plate to the edge, which can solve the problem of bolt spacing.

(5) The dowel bar and the loading plate are connected by a double-section universal joint, which can deflect the steel loading plate in any direction, so that the pulling force of the group anchor is evenly distributed in each bolt during the pull-out test, which effectively prevents the When the model is drawn, the relative distortion between the anchors is caused by the uneven stress distribution.

(6) The automatic leveling support at the bottom of the reaction force frame and the rammed earth box can automatically adjust the level under the action of gravity to solve the problem of uneven ground in the test site.

(7) During the pull-out test, the anchoring force, displacement, and strain energy of the rod and slurry interface of the anchoring mechanism are clearly displayed in real time by the computer.

(8) The loading plate is not directly placed on the rammed earth box, and the damage condition and data measurement of the surface of the rammed layer can be directly observed. The whole system is completely open, which is conducive to the analysis of test data.

Description of drawings

FIG. 1 is a schematic diagram of the overall structure of the anchor pull-out test system for rammed earth sites according to the present invention.

FIG. 2 is a schematic structural diagram of the group anchor anchoring mechanism according to the present invention.

FIG. 3 is a front disassembled view of the rammed earth box according to the present invention.

FIG. 4 is a top view of the box unit according to the present invention.

FIG. 5 is a top disassembly view of the box unit according to the present invention.

FIG. 6 is a front view of the reaction force frame according to the present invention.

Fig. 7 is the left side view of the reaction frame according to the present invention

FIG. 8 is a top view of the four-hole loading plate according to the present invention.

FIG. 9 is a top view of the three-hole loading plate according to the present invention.

FIG. 10 is a schematic structural diagram of the dowel rod according to the present invention.

Detailed ways

The present invention will be further described in detail below with reference to the accompanying drawings, so that those skilled in the art can implement it with reference to the description.

As shown in FIG. 1 , the present invention provides a group anchor pulling test system for a rammed earth site, including a group anchor anchoring mechanism, a loading mechanism, and a data acquisition and processing system.

Referring to FIG. 2 together, the group anchoring mechanism includes a rammed earth box 101, a rammed earth layer 102 is rammed in the rammed earth box 101, and 2-4 anchor holes are arranged in the rammed earth layer 102, and these anchors The holes are evenly arranged at equal intervals relative to the central axis of the rammed earth layer 102 . An anchor rod 103 for testing is set in each anchor hole, and an anchoring slurry 104 is set between the anchor rod 103 and the anchor hole to fix the rammed earth layer 102 and the anchor rod 103 . The bottom of the rammed earth box 101 is provided with an automatic leveling support 105, which can keep the rammed earth box 101 in a horizontal state all the time.

As shown in FIG. 3 , the rammed earth box 101 includes a box base 106 and a plurality of box body units 107 . The box base 106 is arranged at the bottom, and the self-leveling support 105 is arranged at the bottom end of the box base 106 . A plurality of box units 107 are sequentially listed above the box base 106 . Referring to FIG. 4 and FIG. 5 together, the box unit 107 includes four channel steels 108 arranged in a rectangular shape, and two adjacent channel steels 108 are fixedly connected by a locking device 109 to form a box body unit 107 . The number of layers of the box unit 107 may be set according to the thickness of the rammed earth layer 102 .

As shown in FIG. 1 , the loading mechanism includes a reaction force frame 201 , a loading plate 202 , a transmission rod 203 , a hand-held rotary anchor head 204 , a universal joint 205 , a hydraulic oil cylinder 206 and a hydraulic oil pump 207 .

As shown in FIG. 6 and FIG. 7 , the reaction force frame 201 includes two vertical beams 208 arranged in parallel. On the upper part of the vertical beams 208, a plurality of fixing plates 209 are arranged from top to bottom, and the cross beams 210 are placed on the fixing plates. 209 and keep the beam 210 level. The upper and lower positions of the beam 210 can be adjusted by placing the beam 210 on the fixing plate 209 at different positions. The vertical beam 208 and the transverse beam 210 are made of I-beam. The lower part of the vertical beam 208 is provided with a gusset 211 for enhancing the stability of the vertical beam 208 . The bottom of the vertical beam 208 is also provided with an automatic leveling support 212 and a moving wheel 213 . Ribs 214 are provided on the beam 210 to enhance the strength of the beam 210 . The hand-held rotating anchor head 204 is provided in the middle above the beam 210 .

As shown in FIG. 8 and FIG. 9 , the loading plate 202 is circular, and is provided with a plurality of openings 215 . The number of the openings 215 is the same as that of the anchor rods 103 , and the openings 215 are long Slot holes, the length of which is along the radial direction of the loading plate 202 . Ribs 216 are provided on the loading plate 202 for enhancing the strength of the loading plate 202 . The loading plate 202 is fixed to the plurality of anchor rods 103 through the openings 215 .

As shown in FIG. 1 and FIG. 10 , threads are evenly arranged on the dowel rod 203 , the lower end of the dowel rod 203 is connected with the universal joint 205 , and the universal joint 205 is connected with the middle of the loading plate 202 . The upper end of the dowel rod 203 passes through the hole at the center of the beam 210 . The hydraulic cylinder 206 is installed above the beam 210 , and the upper end of the dowel rod 203 passes through the hydraulic cylinder 206 . The hydraulic oil cylinder 206 is connected to the hydraulic oil pump 207 through the hydraulic oil pipe 217 . The hydraulic oil pump 207 is a manual oil pump.

As shown in FIGS. 1 and 2 , the data acquisition and processing system includes a strain gauge 301 attached to the anchor rod 103 , a stress sensor 302 disposed between the hydraulic cylinder 206 and the hand-held rotating anchor head 204 , and a stress sensor 302 The connected displacement measuring device 303, the digital display instrument 304 connected with the stress sensor 302 and the displacement measuring device 303, the strain acquisition instrument 305 connected with the strain gauge 301, and the digital display instrument 304 and the strain acquisition instrument 305 are connected data processor 306. The displacement measuring device 303 includes a magnetic base 307 adsorbed on the surface of the outer column of the stress sensor 302 , and a displacement sensor 308 fixed on the beam 210 and connected to the magnetic base 307 . The displacement of the dowel rod can be measured by the displacement sensor 308 .

As a preferred option, the rammed earth box 101, the self-leveling support 105, the reaction force frame 201, the loading plate 202, the dowel rod 203, the hand-held rotating anchor head 204, and the universal joint 205 are all made of steel materials .

The invention provides a group anchor pull-out test system for rammed earth sites. When in use, the first choice is to level the site and place the rammed earth box. Level. To compact the rammed earth in layers, first ram the rammed earth layer in the bottom layer of the rammed earth box. As the bottom layer of the rammed earth, four channel steels are spliced into a box unit through the locking device, so that an additional layer of the rammed earth box is added. The rammed earth layers are rammed, and so on, until the number of rammed earth layers required for the test. In addition to the bottom layer of the rammed earth, anchor holes at equal distances from the center of the rammed earth box are reserved in the rammed earth layer. The rammed earth layer is the original collapsed soil sample of the rammed earth site, which is manually rammed according to the construction technology of the rammed earth site.

The strain gauges are pasted and arranged in the anchoring section of the test bolt, and the number of strain gauges depends on the research requirements. After the rammed soil layer is dry, inject grout into the anchor hole, insert the test anchor rod, and fill up the grout; reserve a certain length of anchor rod outside the rammed layer for pulling.

The hydraulic cylinder is placed on the beam of the reaction frame, the stress sensor is placed on the cylinder, the steel dowel rod passes through the circular hole of the beam of the reaction frame, the oil cylinder, and the stress sensor from bottom to top, and the top is rotated by the hand-held rotary anchor head. Make sure that the center hole of the reaction frame, the hydraulic cylinder, the stress sensor and the center line of the dowel rod coincide. Connect the loading plate and the dowel rod through a two-section universal joint; move the reaction frame to the top of the rammed earth box, make the bolt symmetrically pass through the opening of the loading plate, and ensure that the center of the dowel rod and the center of the rammed earth box coincide . Put the anchor on the anchor rod, place it on the loading plate, and use the clip to firmly bond the anchor with the test anchor rod; at the same time, rotate the top steel hand-held rotating anchor head again to reduce the displacement loss during the test. .

The strain wire connected to the strain gauge is drawn out and connected to the strain acquisition instrument; the strain acquisition instrument is connected to the data processor, and the strain amount of the test bolt is monitored in real time during the test. The hydraulic oil cylinder is connected with the hydraulic manual pump through the hydraulic oil pipe, and the hydraulic oil cylinder is manually pressurized manually during the test. Connect the stress sensor to the digital display through the sensor cable to monitor the current stress value in real time. The displacement meter is adsorbed on the surface of the outer column of the stress sensor through the magnetic table base, and then the displacement sensor is connected to the digital display instrument through the sensor connection line to monitor the current displacement value in real time. Connect the digital display instrument to the data processor through a wire, record and store the load-displacement curve.

During the test, manually pressurize the hydraulic oil pump, and the oil pressure transmitted through the hydraulic oil pipe makes the piston in the oil cylinder rise, and transmits it to the loading plate through the dowel rod. The loading plate evenly distributes the load to each test anchor rod to provide pulling The required load; the reaction force applied by the cylinder is transmitted to the ground through the reaction frame. During the drawing process, the anchoring force of the group anchor system, the displacement of the anchor rod, and the strain of the rod body and the slurry interface are controlled and monitored by the digital display instrument, the strain acquisition instrument and the data processor; the macroscopic failure mode of the group anchor system is observed and recorded through the test phenomenon, and the measurement Destroy data such as spacing, margins, etc. By adjusting the variables such as the length of the anchor rod, the diameter of the anchor rod, the size of the anchor hole, the spacing of the anchor rod and the margin, the group anchoring effect of the anchor rod in the rammed earth site is revealed, and the scientific basis for the anchorage design is provided.

Although the embodiment of the present invention has been disclosed as above, it is not limited to the application listed in the description and the embodiment, and it can be applied to various fields suitable for the present invention. For those skilled in the art, it can be easily Therefore, the invention is not limited to the specific details and illustrations shown and described herein without departing from the general concept defined by the appended claims and the scope of equivalents.

Claims (9)

1. a kind of building earthen ruins group anchor pull-out test system, which is characterized in that including group's anchor anchoring mechanism, loading mechanism and Data Collection & Processing System；

Group's anchor anchoring mechanism includes rammed earth case, and building has rammed earth layer in rammed earth case, is provided in the rammed earth layer multiple Anchor hole, the multiple anchor hole are equally evenly arranged relative to rammed earth layer central axis；Anchor pole, the anchor are provided in anchor hole Anchoring slurries are provided between bar and anchor hole；

The rammed earth case includes block and the multiple box units arranged along the vertical direction above block, the cabinet list is arranged in Member includes four channel steels in rectangular arranged, and two neighboring channel steel is fixedly connected by locker；

The loading mechanism be anchor pole apply pulling force, and by data Collection & Processing System monitor anchor force, anchor pole strain and Displacement；The loading mechanism includes:

Load plate is provided with aperture, is fixed load plate and anchor pole by the aperture；

Transmission rod, lower end in the middle part of two-segment type universal joint and load plate by connecting；Screw thread is disposed in the transmission rod circumferential direction； Floor is arranged in load plate upper surface, is divided into 4 cellular type load plates and 3 cellular types load version, aperture is from load plate center to edge；

Reaction frame, the transmission rod upper end are passed through from the reaction frame；Reaction frame is detachable apparatus, and crossbeam can pass through crossbeam Support adjusts height, span；

Hydraulic cylinder is arranged on the reaction frame, and passes through transmission rod from the hydraulic cylinder；

Hand-held rotary anchor head, is arranged above the hydraulic cylinder, the hand-held rotary anchor head and the screw thread phase on transmission rod Cooperation, by power transmission rod locking；

Oil pump is connect with the hydraulic cylinder, to provide pressure for hydraulic cylinder.

2. building earthen ruins group anchor pull-out test system according to claim 1, which is characterized in that the reaction frame includes The vertical beam of two parallel arrangements is provided with multiple fixed plates on the top of vertical beam from top to bottom, and it is solid that crossbeam is placed on left and right two On fixed board and keep crossbeam horizontal.

3. building earthen ruins group anchor pull-out test system according to claim 2, which is characterized in that the vertical beam lower end is set It is equipped with angle brace, the vertical beam bottom is additionally provided with automatic leveling support and movable pulley.

4. building earthen ruins group anchor pull-out test system according to claim 2, which is characterized in that data acquisition with Processing system includes:

Foil gauge is attached on anchor pole, to measure the strain of anchor pole；

Strain gauge is arranged between hydraulic cylinder and hand-held rotary anchor head, to measure anchor force；

Displacement measuring device comprising be adsorbed on the Magnetic gauge stand on strain gauge column jacket surface, and be fixed on crossbeam and with The displacement sensor of Magnetic gauge stand connection, to measure the displacement of anchor pole；

Digital display instrument is connect with the strain gauge and displacement sensor；

Strain acquirement instrument is connect with the foil gauge；

Data processor is connect with the digital display instrument and strain acquirement instrument.

5. building earthen ruins group anchor pull-out test system according to claim 1, which is characterized in that rammed earth bottom portion It is provided with automatic leveling support.

6. building earthen ruins group anchor pull-out test system according to claim 1, which is characterized in that the anchor hole is provided with 2-4.

7. building earthen ruins group anchor pull-out test system according to claim 1, which is characterized in that the anchor pole is using wood One of anchor pole, bamboo anchor pole, bamboo reinforcement Composite Bolt and glass fibre anchor pole.

8. building earthen ruins group anchor pull-out test system according to claim 1, which is characterized in that the oil pump is manual Oil pump.

9. building earthen ruins group anchor pull-out test system according to claim 1, which is characterized in that the rammed earth layer adds The axis coaxle arrangement of support plate, transmission rod, hydraulic cylinder, strain gauge.