CN210636477U - Pressure type anchor rod bearing characteristic model test device under action of horizontal load - Google Patents
Pressure type anchor rod bearing characteristic model test device under action of horizontal load Download PDFInfo
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- CN210636477U CN210636477U CN201921222116.4U CN201921222116U CN210636477U CN 210636477 U CN210636477 U CN 210636477U CN 201921222116 U CN201921222116 U CN 201921222116U CN 210636477 U CN210636477 U CN 210636477U
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Abstract
The utility model provides a pressure type anchor rod bearing characteristic model test device under the action of horizontal load, which comprises a transparent model box with an opening on the side surface, a loading device and a soil pressure monitoring device, wherein the loading device is positioned on one side of the opening of the model box; a pressure type anchor rod is arranged on one side surface of the model box adjacent to the opening and clings to the inner wall of the box body, and a dial indicator is arranged at the top end of the outer side of the anchor rod body; a baffle is arranged on one side of the opening of the model box, and a hole for the rod body to pass through is formed in the baffle; the loading device comprises an adjustable loading support, a fixed pulley on the adjustable loading support and a connecting wire wound around the fixed pulley, wherein one end of the connecting wire is connected with an anchor rod, and the other end of the connecting wire is connected with a weight tray for containing weights; the soil pressure monitoring devices are distributed in the sand-gravel soil for the test in the model box according to a certain arrangement mode. The test device ensures that the anchor rods under different burial depth conditions can be subjected to horizontal load, and in addition, the device can also perform horizontal tension tests on a plurality of anchor rods simultaneously.
Description
Technical Field
The utility model belongs to the technical field of underground geotechnical engineering, a model test device is related to, concretely relates to horizontal load effect down pressure type stock bears characteristic model test device.
Background
The geotechnical pre-stressed anchoring technology has the advantages of small disturbance to rock and soil mass, quick construction, safety, economy and the like, is increasingly the first choice method in rock and soil reinforcement engineering of high slopes, dams and the like, and obtains great economic and social benefits. According to its interior anchor section atress form can be divided into pulling force type stock and pressure type stock, pulling force type stock utilizes body of rod and slip casting body, the interface shear stress between slip casting body and the surrounding rock body provides resistance to plucking anchoring force, consequently only be applicable to in the stable rock stratum, and pressure type stock mainly relies on the anchor plate that is located the stock end to provide resistance to plucking bearing capacity to the compressive stress of its anterior soil body, the atress mechanism is more reasonable, consequently mostly as structures such as horizontal atress structure and retaining wall cooperation be used for among the soil property fill side slope reinforcement engineering, or as vertical atress structure and be applied to among the anti-superficial reinforcement engineering of underground building. As a novel prestressed anchoring structure, the stress mechanism of a pressure type anchor rod is complex, the research on the force transmission mechanism and the working characteristics of the pressure type anchor rod is still in the starting stage at present, a reasonable design calculation method is lacked, in particular, deep theoretical and experimental researches are lacked in the aspects of determination of the limit bearing capacity of a single or a plurality of anchor rods, development and evolution rules of a body pressure stress field and a shear strain field around a rod body under the action of load and the like in the design, and the popularization and application of the novel structure in geotechnical reinforcement engineering are limited due to the shortage of the theoretical researches. Therefore, the bearing characteristic problem of the pressure type anchor rod has attracted wide attention in the engineering field at home and abroad.
At present, a numerical simulation or on-site full-scale test mode is mainly adopted for a research method for the bearing characteristics of the pressure type anchor rod, the deformation and development rules of soil around the rod body under the action of load cannot be observed visually, and the deformation rules of the soil are closely related to the bearing characteristics of the pressure type anchor rod. The invention patent with application number 201810309931.8, a pressure dispersion type anchor rod anchoring mechanism visual model test device and a test method, discloses a research method and a device for the pressure dispersion type anchor rod anchoring mechanism under the action of vertical load, but the research object is mainly a pressure type anchor rod bearing the vertical load, the pressure type anchor rods adopted in the prior embankment high slope reinforcement are all stressed horizontally, the soil body stress field and the displacement field caused by the horizontal stress of the anchor rods are asymmetrically distributed on two sides of a rod body, which are completely different from the symmetrical soil body stress and the displacement field which are expressed by the vertical stress of the rod body and take the central line of the anchor rod as a symmetrical axis, and the bearing characteristics of the two are also determined to have great difference. In addition, the aforementioned patent only adopts a visual model test mode to analyze the soil body stress field on the observation surface, and cannot form a three-dimensional and spatial soil body pressure stress field distribution form.
SUMMERY OF THE UTILITY MODEL
The utility model discloses a characteristic model test device is born to horizontal load effect down pressure type stock can conveniently carry out the visual observation to the bearing characteristic of bearing the single or many pressure type stocks of horizontal load under the different buried depth condition to the accessible is buried the spatial distribution and the change law of monitoring element analysis horizontal load effect down pressure type stock soil body compressive stress field all around underground.
In order to achieve the technical purpose, the utility model discloses a following technical scheme realizes:
the pressure type anchor rod bearing characteristic model test device under the action of horizontal load comprises a transparent model box with an opening on the side surface, a loading device and a soil pressure monitoring device, wherein the loading device is positioned on one side of the opening of the model box;
at least one pressure type anchor rod is arranged on one side surface of the model box adjacent to the opening and clings to the inner wall of the box body, the pressure type anchor rod comprises a rod body and an anchor plate vertical to the rod body, and the rod body is parallel to the bottom surface of the box body; the top end of the rod body is provided with a dial indicator; a baffle is arranged on one side of the opening of the model box, and a hole for the rod body to pass through is formed in the baffle;
the loading device comprises an adjustable loading support, a fixed pulley on the adjustable loading support and a connecting wire wound around the fixed pulley, wherein one end of the connecting wire is connected with an anchor rod, and the other end of the connecting wire is connected with a weight tray for containing weights;
the soil pressure monitoring devices are distributed in a test soil body in the model box.
The soil pressure monitoring device is a soil pressure meter, and the soil pressure meters are distributed according to a certain arrangement mode.
The anchor rods are connected through the loading strips, one end of the connecting wire is connected with the loading strips, and the other end of the connecting wire is connected with a weight tray for holding weights;
the side that the pressure type stock is hugged closely is the observation face adjacent with the opening side.
Preferably, a protection device is arranged on the outer side of the bottom of the model box, the protection device comprises a rectangular bottom plate, a protection plate is vertically connected to the bottom plate, a space for accommodating the model box is formed by the rectangular bottom plate and the vertically arranged protection plate, and the model box is arranged in the protection device; and a detachable baffle is arranged between one side of the opening of the model box and the protection device.
The connecting line between the anchor rods and the fixed pulleys is in the horizontal direction, and the connecting line between the fixed pulleys and the weight tray is vertically downward.
Protection device's bottom plate has carried out the extension, adopts the diagonal bracing to fix between bottom plate outward flange and the backplate, places the heavy object on the extension bottom plate before the experiment, prevents that the device from producing the toppling under the effect of great moment.
Preferably, the adjustable loading support comprises a horizontal fixed platform and an adjustable supporting leg below the fixed platform, and the fixed pulley is fixedly installed on the fixed platform.
Further preferably, the number of the adjustable supporting legs is three, and the included angle between the three supporting legs is 120 degrees.
Further preferably, the leg is angled at 60 ° to the horizontal.
Preferably, the leg comprises an upper structure and a lower structure, the lower structure is a hollow structure, and the upper structure is inserted into the lower hollow structure. The upper structure and the lower structure are provided with a plurality of bolt holes and fixedly connected through bolts. The height of the legs can be adjusted by adjusting the relative positions of the upper and lower structures.
The loading support can adjust the height so as to meet the requirement of anchor rod horizontal stress under different burial depths. The fixing bolts on the three supporting legs are pulled out, the upper structure and the lower structure of the supporting legs can be adjusted in an up-and-down movement mode, and the bolts are inserted into the reserved holes after the required height is achieved, so that the supporting legs can be fixed.
The supporting legs are connected with the fixed table, the fixed table and the fixed pulleys in a welding mode.
The fixed pulley and the connecting line are arranged on the extension line where the rod body is located.
Preferably, the cross section of the guard plate is right-angled and is positioned outside the vertical edge of the model box.
Preferably, the number of the guard plates is four, the model box is cuboid, and the guard plates are positioned on the outer side of the model box body to play roles in stabilizing and protecting.
Preferably, the anchor plate of the pressure type anchor is rectangular. The anchor plate comprises two rectangular plates which are positioned at the same side of the rod body.
Preferably, the top end of the rod body is provided with a connecting hole, and the connecting hole is connected with the loading device through a connecting wire.
Preferably, the base of the dial indicator is connected to the protection device, and the gauge head is tightly pressed on the top end of the anchor rod body. The dial indicator is used for measuring the displacement generated by the anchor rod, and the measuring rod of the dial indicator is arranged in parallel with the moving direction of the anchor rod. The anchor rod moves when being subjected to horizontal load, the moving direction is the load applying direction, and the measuring rod of the dial indicator is arranged in parallel with the moving direction, so that the measuring accuracy can be ensured.
The digital camera is arranged on the main viewing surface of the model box. The digital camera is placed outside the box body, the anchor rod is arranged in the middle of the lens, the lens is flush with the central axis of the anchor rod, and clear pictures can be conveniently taken for analyzing clear images of the sand and gravel soil for the model box side test.
Further preferably, the base of the dial indicator is a universal magnetic gauge stand, the protection device is iron, and the gauge stand is adsorbed on the iron protection device.
Preferably, the arrangement mode of the soil pressure gauges is as follows: the central axis of the rod body is taken as a symmetry axis and is distributed up and down symmetrically.
Further preferably, two soil pressure gauges symmetrical with respect to the rod body are provided in one group, and the soil pressure gauges are provided in 8 groups.
Further preferably, the soil pressure gauges are provided with a first group and a second group at two anchor plates, then a third group and a fourth group are arranged at the same interval along the axial direction of the rod body, and 5-8 groups of soil pressure gauges are respectively arranged at the positions of the horizontal plane where the 4 groups of soil pressure gauges are arranged at intervals along the radial direction of the rod body.
Preferably, the soil pressure gauge is connected with the static strain gauge, and the stress condition of the sand and gravel soil for the peripheral test under the condition that the anchor rod is loaded is monitored. The utility model discloses well pressure type stock is the half module stock of making according to similar principle. The similarity principle means that the anchor rod in the test is a model anchor rod which is designed according to the anchor rod in actual engineering and according to a certain geometric similarity ratio and modulus similarity ratio, slightly different in size and material and completely identical in stress mechanism.
Preferably, the anchor rod is pasted with the high temperature rubber self-adhesive tape with the one side of model box contact, and the effect of high temperature rubber self-adhesive tape is that prevent experimental sand and stone soil granule from slipping into between anchor rod and the glass, then hug closely the smooth side of anchor rod at the subjective face of surveying of transparent model box.
Preferably, the baffle is an independently detachable rectangular iron plate for preventing the test sand in the mold box from leaking outwards. The baffle plate is as wide as the opening surface of the model box, and the height of the baffle plate is four fifths of the height of the opening surface.
Leave a plurality of horizontally arranged's square hole on the baffle, the square hole size is the same with body of rod size to conveniently carry out horizontal loading to the stock. In the reserved square holes, the height of the square hole at the bottom from the lower edge of the baffle plate accounts for one third of the height of the whole baffle plate, and in the same way, the height of the square hole at the top from the upper edge of the baffle plate is also one third. In order to observe the stress movement condition of the anchor rod in the glass box, the anchor rod needs to be tightly attached to the wall of the glass box, so that the baffle plate needs to be perforated at a corresponding position, the end part of the anchor rod is conveniently exposed, a part of the anchor rod is conveniently loaded, the shape of the square hole is consistent with the shape of the cross section of the rod body, and the anchor rod is ensured to just penetrate through the square hole. The size of the space between the adjacent square holes is consistent with the width of the anchor rod body. Because the later stage needs analysis stock interval to its influence law that bears the weight of the characteristic, it is the same to set up the interval between the adjacent square hole, can conveniently confirm the interval of stock through the figure in square hole to can guarantee the degree of accuracy of interval. The square hole that no stock passed can be plugged up with the rubber stopper, prevents to leak sand, and the square hole can be selectively opened when needing to pass the stock and use.
Preferably, the mold box is a glass box body.
When the stock is many stocks, the top of many stocks is connected to the loading strip, through applying horizontal load to the loading strip, carries out the drawing test of many stocks. The loading strip is made of a thin rectangular aluminum plate, the dead weight is light, and errors generated by the dead weight in a test can be ignored. The size and the position of the opening on the loading strip are consistent with those of the square hole on the baffle. When a plurality of anchor rods penetrate through the square holes in the baffle plate, the loading strips can be sleeved on the extending parts of the anchor rods. When applying the load, the connecting wire applies the load to the loading strip to guarantee that many stock receive horizontal load effect simultaneously. The end part of the anchor rod is provided with a connecting hole for threading, and after the anchor rod passes through the loading strip, the connecting hole is inserted into a bolt to prevent the loading strip from sliding out under stress.
The rammer weight is 2.0kg, and is used for layering and ramming of sandy soil for the test.
The pressure type anchor rod is a half-mold anchor rod manufactured according to a similar principle.
The utility model provides a case lateral wall of mold box is formed by four organic glass equipment, and the box is the cuboid structure, and digital camera shoots at the main observation surface of box when testing, and organic glass's junction seals with the waterproof glue.
Preferably, the sandy soil for the test is prepared by adding medium coarse sand into limestone broken stone aggregate, wherein the particle diameter of the medium coarse sand is less than 20% of the total mass of 2.00mm, the particle diameter of the medium coarse sand is 30% of the total mass of 2.00-4.75 mm, and the particle diameter of the medium coarse sand is 50% of the total mass of 4.75-9.50 mm.
Preferably, the connecting line of the loading device adopts a stainless steel wire rope with the diameter of 2.0mm, and the maximum load bearing capacity of the stainless steel wire rope is 150 kg.
The method for testing the bearing characteristic model of the pressure type anchor rod under the action of the horizontal load comprises the following steps:
step one, building a visual model test device
Placing the model box into a protection device, placing a baffle plate into a reserved seam between the protection device and the glass box, and ensuring that the baffle plate is tightly attached to one side of an opening of the glass box;
step two, filling the sandy soil for the test in layers, embedding the anchor rod, the soil pressure monitoring device and the like
Filling the test sand and stone soil into the model box layer by layer, and manually tamping the test sand and stone soil layer by using a tamping hammer so as to ensure the compactness of the test sand and stone soil in the model box; when the pressure type anchor rod is filled to the designed height, the pressure type anchor rod is horizontally placed, the top end of the rod body is aligned with the opening of the baffle plate, the end part of the rod body penetrates through the reserved hole to extend out of a part of the rod body, and the side surface of the anchor rod is tightly contacted with the glass of the main view surface of the model box; burying a soil pressure gauge at a preset position, and leading out leads of the soil pressure gauge from a model box in sequence; then filling the sandy soil for the test layer by layer, tamping the sandy soil layer by layer until the design height of the filled soil is reached, and finally leveling the surface of the sandy soil for the test; placing a heavy object on the epitaxial bottom plate to ensure the stability of the test device;
step three, debugging the test equipment
The connecting wire is wound around a fixed pulley on the upper part of the adjustable loading bracket, one end of the connecting wire is connected to the weight plate, and the other end of the connecting wire is connected to a connecting hole at the end part of the pressure type anchor rod; if the number of the anchor rods is two or more, connecting the connecting line to the loading strip; erecting a digital camera on the main view surface of the model box, and adjusting the position and parameters of the camera to enable the focal plane of the camera to be parallel to the main view surface of the model box and shoot clear sand-stone soil images for the test; pressing the gauge head of the dial indicator on the top end surface of the pressure type anchor rod; sequentially connecting the soil pressure gauge lead to a static strain gauge, and connecting the static strain gauge to a computer to complete debugging;
step four, start the test
Adding weights on a weight tray, carrying out graded loading on the pressure type anchor rod, recording stress data of the soil pressure gauge through a static strain gauge, respectively shooting images of the sandstone soil for the box side test under each level of load in the test process by using a digital camera, and loading until the value of a dial indicator at the top end of the pressure type anchor rod under constant horizontal load is continuously increased;
step five, analyzing test results
After the test loading is finished, a soil body pressure stress field around the anchor rod under the graded load is obtained by analyzing the soil pressure count value; analyzing images shot by a digital camera in the test process through image processing software to obtain a displacement field and a shear strain field of the soil body around the rod under different loads; and obtaining a load-displacement curve of the rod body through a dial indicator.
When two or many stock carry out horizontal loading, need link together two or many stock through the loading strip, receive the load through loading strip level and transmit the load to two or many stock to guarantee that two or many stock can receive the horizontal load effect simultaneously.
The utility model has the advantages that:
this testing device has not only solved the experimental visual problem of horizontal load effect down pressure type stock bearing characteristic, and loading support can height-adjusting moreover, has guaranteed that the stock all can bear the horizontal load effect under the different buried depth condition, can also draw the experiment simultaneously to many stocks in addition. In the drawing test of many stock, the stock interval can accurate regulation to the experimental simulation under the multiple operating mode of adaptation. The burying of the soil pressure monitoring device can reveal the spatial evolution law of the compressive stress field of the soil body around the rod under different grading loads.
Drawings
FIG. 1 is a front view of the single anchor testing device of the present invention;
FIG. 2 is a top view of the single anchor testing device of the present invention;
FIG. 3 is a schematic structural view of a mold box protection device of the present invention;
FIG. 4 is a front view of the dual anchor testing device of the present invention;
FIG. 5 is a schematic view of the baffle structure of the present invention;
fig. 6 is a schematic structural view of the loading bar of the present invention;
fig. 7 is a schematic view of the pressure type anchor rod structure of the present invention.
Reference numerals:
1. the device comprises a weight tray, 2, an adjustable loading support, 2a, an upper structure, 2b, a lower structure, 2c, an adjusting bolt, 3, a fixed pulley, 4, a connecting wire, 5, a model box, 6, a guard plate, 7, a baffle, 8, a pressure type anchor rod, 8a, a rod body, 8b, a connecting hole, 8c, a rectangular anchor plate, 9, a dial indicator, 10, a loading device fixing plate, 11, a loading strip, 12 and a soil pressure gauge.
Detailed Description
Example 1
As shown in fig. 1 to 7, the model test device for the load bearing characteristics of the pressure type anchor rod under the action of the horizontal load of the embodiment of the present invention comprises a transparent model box 5 with an opening on the side surface and a loading device, wherein the loading device is positioned on one side of the opening of the model box 5;
the outer side of the bottom of the model box 5 is provided with a protection device, the protection device comprises a rectangular bottom plate, a protection plate 6 is vertically connected onto the bottom plate, the rectangular bottom plate and the vertically arranged protection plate 6 form a space for accommodating the model box 5, and the model box 5 is arranged in the protection device; a detachable baffle 7 is arranged between one side of the opening of the model box 5 and the protection device;
a pressure type anchor rod is arranged on one side face of the model box 5 and clings to the inner wall of the box body, the pressure type anchor rod comprises a rod body 8a and an anchor plate perpendicular to the rod body 8a, and the rod body 8a is parallel to the bottom face of the box body; the top end of the rod body 8a is provided with a dial indicator 9; the baffle 7 is provided with a hole for the rod body 8a to pass through;
the loading device comprises an adjustable loading support 2, a fixed pulley 3 on the adjustable loading support 2 and a connecting wire 4 wound around the fixed pulley, wherein one end of the connecting wire 4 is connected with a connecting hole or a loading strip at the top end of a rod body 8a, and the other end of the connecting wire 4 is connected with the weight tray 1;
a plurality of soil pressure gauges 12 are arranged in the model box 5.
And an oblique reinforcing rib is arranged between the guard plate 6 and the bottom plate.
The connecting line between the top end of the rod body 8a and the fixed pulley is in the horizontal direction, and the connecting line between the fixed pulley and the weight tray 1 is vertically downward.
Protection device's bottom plate has carried out the extension, adopts the slant strengthening rib to fix between bottom plate outward flange and the backplate, places the heavy object on the extension bottom plate before the experiment, prevents that the device from producing the toppling under the effect of great moment.
The adjustable loading support 2 comprises a horizontal fixing table and adjustable supporting legs below the fixing table, and the fixed pulley 3 is fixedly installed on the fixing table. The adjustable landing leg is three, and the contained angle between three landing legs is 120. The included angle between the supporting legs and the horizontal plane is 60 degrees. The leg comprises an upper structure 2a and a lower structure 2b, the lower structure 2b is a hollow structure, and the upper structure 2a is embedded into the lower hollow structure. The upper structure 2a and the lower structure 2b are provided with a plurality of bolt holes, and the upper structure 2a and the lower structure 2b are fixedly connected through bolts. By adjusting the relative position of the upper structure 2a and the lower structure 2b, the height of the legs can be adjusted. The loading support can adjust the height so as to meet the requirement of anchor rod horizontal stress under different burial depths. The fixing bolts on the three supporting legs are pulled out, the upper structure 2a and the lower structure 2b of the supporting legs can be adjusted in an up-and-down movement mode, and the bolts are inserted into the reserved holes after the required height is achieved, so that the supporting legs can be fixed. The supporting legs are connected with the fixed table, the fixed table and the fixed pulleys through welding. The lower structure 2b of the supporting leg is welded with the loading device fixing plate 10, and the stabilizing effect is achieved.
The fixed pulley and the connecting line are arranged on the extension line of the rod body 8 a.
The cross section of the guard plate 6 is right-angled and is positioned outside the vertical edge of the model box 5. The number of the guard plates 6 is four, the model box 5 is cuboid, and the guard plates 6 are located on the outer side of the model box body 5 and play roles in stabilizing and protecting. The model box 5 is a glass box body.
The anchor plate of the pressure type anchor rod is a rectangular anchor plate 8 c. The anchor plate includes two rectangular plates, and two rectangular plates are located the homonymy of the body of rod 8 a. The top end of the rod body 8a is provided with a connecting hole 8 b. The connecting hole 8b is connected with the loading device through a connecting line 4. The anchor rod is pasted with the high temperature rubber self-adhesive tape with the one side of model box 5 contact, and the effect of high temperature rubber self-adhesive tape is that prevent experimental sand stone soil granule from slipping into between anchor rod and the glass, then hug closely the smooth section of anchor rod at the subjective face of surveying of transparent model box 5.
The base of the dial indicator 9 is arranged on the protection device, and the gauge head is tightly pressed on the top end of the anchor rod body 8 a. The dial indicator 9 is used for measuring the displacement of the anchor rod under horizontal load. The dial indicator measuring rod is arranged in parallel with the moving direction of the anchor rod. The anchor rod moves when being subjected to horizontal load, the moving direction is the load applying direction, and the measuring rod of the dial indicator 9 is arranged in parallel with the moving direction, so that the measuring accuracy can be ensured. The base of the dial indicator 9 is a universal magnetic gauge stand, the protection device is iron, and the gauge stand is adsorbed on the iron protection device.
The digital camera is arranged on the main viewing surface of the model box. The digital camera is placed outside the box body, the anchor rod is arranged in the middle of the lens, the lens is flush with the central axis of the anchor rod, and clear pictures can be conveniently taken for analyzing clear images of the sand and gravel soil for the 5-box side test of the model box.
The soil pressure gauges 12 are vertically symmetrically arranged about the anchor rod body 8 a. The first and second groups of soil pressure gauges 12 are closely attached to the anchor plate, then the third and fourth groups are arranged at the same interval along the axial direction of the anchor rod body 8a, and the 5 th to 8 th groups of soil pressure gauges, which are 16 soil pressure gauges 12 in total, are respectively arranged at the positions of the horizontal plane where the 4 groups of soil pressure gauges are located and at intervals of the width of the anchor plate along the radial direction of the anchor rod body. The soil pressure gauge 12 is connected with a static strain gauge and used for monitoring the stress condition of the sand and stone soil for the peripheral test under the condition that the anchor rod is loaded. The utility model discloses well pressure type stock 8 is the half module stock of making according to similar principle. The similarity principle means that the anchor rod in the test is a model anchor rod which is designed according to the anchor rod in actual engineering and according to a certain geometric similarity ratio and modulus similarity ratio, slightly different in size and material and completely identical in stress mechanism.
The baffle 7 is an independent and detachable rectangular iron plate and is used for preventing the sand and gravel soil for the test in the model box 5 from leaking outwards. The baffle 7 has the same width with the opening surface of the model box 5, and the height is four fifths of the height of the opening surface. A plurality of horizontally arranged square holes are reserved on the baffle 7, and the size of each square hole is the same as the size of the rod body, so that the anchor rod can be conveniently and horizontally loaded. In the reserved square holes, the height of the square hole at the bottom from the lower edge of the baffle 7 accounts for one third of the height of the whole baffle 7, and in the same way, the height of the square hole at the top from the upper edge of the baffle 7 is also one third. In order to observe the stress movement condition of the anchor rod in the glass box, the anchor rod is required to be tightly attached to the wall of the glass box, so that the baffle 7 is required to be perforated at a corresponding position, the end part of the anchor rod is conveniently exposed, a part of the anchor rod is conveniently loaded, the shape of the square hole is consistent with the shape of the cross section of the rod body 8a, and the rod body is ensured to just pass through. The size of the space between the adjacent square holes is consistent with the width of the rod body 8 a. Because the later stage needs analysis stock interval to its influence law that bears the weight of the characteristic, it is the same to set up the interval between the adjacent square hole, can conveniently confirm the interval of stock through the figure in square hole to can guarantee the degree of accuracy of interval. The square hole that no stock passed can be plugged up with the rubber stopper, prevents to leak sand, and the square hole can be selectively opened when needing to pass the stock and use.
The stock if for two stocks or many stocks, two stocks or many stocks connect into a whole through loading strip 11, and loading strip 11 connects the top of two or more stocks, through exerting horizontal load to loading strip 11, carries out the drawing test of two or many stocks. The loading strip 11 is made of a thin rectangular aluminum plate, the self weight is light, and errors generated by the self weight in the test can be ignored. The size and the position of the opening on the loading strip 11 are consistent with those of the square hole on the baffle 7. When two or more anchor rods pass through the square hole on the baffle 7, the loading strip 11 can be sleeved on the parts where the two or more anchor rods extend. When applying the load, the load is applied to loading strip 11 to the connecting wire to guarantee that two or more stock receive horizontal load effect simultaneously. The end part of the anchor rod is provided with a connecting hole for threading, and after the anchor rod passes through the loading strip 11, a bolt is inserted into the connecting hole to prevent the loading strip 11 from slipping out under stress.
The rammer weight is 2.0kg, and is used for layering and ramming of sandy soil for the test. The pressure type anchor rod 8 is a half-mold anchor rod manufactured according to a similar principle.
The utility model provides a mold box 5's case lateral wall is formed by the equipment of four organic glass, and the box is the cuboid structure, and digital camera shoots at the box main face of looking when testing, and organic glass's junction seals with the waterproof glue.
The sandy soil for the test is prepared by adding medium coarse sand into limestone broken stone aggregate, wherein the particle diameter of the medium coarse sand is less than 20% of the total mass of the limestone broken stone aggregate, the particle diameter of the medium coarse sand is 2.00-4.75 mm of the medium coarse sand, and the particle diameter of the medium coarse sand is 30% of the total mass of the limestone broken stone aggregate, and the particle diameter of the medium coarse sand is 4.75-9.50 mm of the medium coarse sand. The connecting line 4 of the loading device adopts a stainless steel wire rope with the diameter of 2.0mm, and the maximum load bearing capacity is 150 kg.
Example 2
The utility model also provides a horizontal load effect down force type stock bears characteristic model test method, including following step:
step one, building a visual model test device
A solid and stable horizontal ground is selected, and a model box protection device is placed to ensure that the protection device is tightly attached to the ground and does not shake. Carefully placing the model box into a protection device, placing a baffle into a reserved seam between the protection device and the glass box, and ensuring that the baffle is tightly attached to one side of an opening of the glass box;
step two, filling the sandy soil for the test in layers, embedding the anchor rod, monitoring the soil pressure and the like
Filling the sandstone soil for the test into the model box layer by layer, wherein the layering height is 5cm, and manually tamping the sandstone soil layer by using a tamping hammer to ensure the compactness of the sandstone soil for the test in the model box. When the pressure type anchor rod is filled to the designed height, the pressure type anchor rod is horizontally placed, the top end of the rod body is aligned with the opening of the baffle plate, the end part of the rod body penetrates through the reserved hole to extend out of a part of the rod body, and the side surface of the anchor rod is in close contact with the glass of the main viewing surface of the model box. And burying a soil pressure gauge at a preset position, and sequentially leading out the leads of the soil pressure gauge from the model box. Then filling the sandy soil for the test layer by layer, tamping layer by layer until the design height of the filled soil is reached, and finally leveling the surface of the sandy soil for the test. Placing a heavy object on the epitaxial bottom plate to ensure the stability of the test device;
step three, debugging the test equipment
The connecting wire is wound around a fixed pulley on the upper part of the adjustable loading bracket, one end of the connecting wire is connected to the weight plate, and the other end of the connecting wire is connected to a connecting hole at the end part of the pressure type anchor rod; if two or more anchor rods, the connecting line is connected to the loading bar. Erecting a digital camera on the main view surface of the model box, adjusting the position and parameters of the camera to enable the focal plane of the camera to be parallel to the front surface of the model box and shooting a clear sand-gravel soil image for the test; pressing the gauge head of the dial indicator on the top end surface of the pressure type anchor rod; and sequentially connecting the soil pressure gauge lead to the static strain gauge, and connecting the static strain gauge to a computer to finish debugging.
Step four, start the test
Adding weights on a weight tray, carrying out graded loading on the pressure type anchor rod, recording stress data of the soil pressure gauge through a static strain gauge, respectively shooting images of the sandstone soil for the box side test under each level of load in the test process by using a digital camera, and loading until the value of a dial indicator at the top end of the pressure type anchor rod under constant horizontal load is continuously increased;
step five, analyzing test results
After the test loading is finished, a soil body pressure stress field around the anchor rod under the graded load is obtained by analyzing the soil pressure count value; analyzing images shot by a digital camera in the test process through image processing software to obtain a displacement field and a shear strain field of the soil body around the rod under different loads; and obtaining a load-displacement curve of the rod body through a dial indicator.
When two or many stock carry out horizontal loading, need link together two or many stock through the loading strip, receive the load through loading strip level and transmit the load to two or many stock to guarantee that two or many stock can receive the horizontal load effect simultaneously.
Claims (9)
1. The pressure type anchor rod bearing characteristic model test device under the action of horizontal load is characterized by comprising a model box (5), a loading device and a soil pressure monitoring device, wherein the model box (5) is a transparent model box with an opening on the side surface, and the loading device is positioned on one side of the opening of the model box (5);
a pressure type anchor rod is arranged on one side surface of the model box (5) adjacent to the opening and clings to the inner wall of the box body, the pressure type anchor rod comprises a rod body (8a) and an anchor plate (8c) vertical to the rod body (8a), and the rod body (8a) is parallel to the bottom surface of the box body; the top end of the rod body (8a) is provided with a dial indicator (9); a baffle (7) is arranged on one side of the opening of the model box (5), and a hole for the rod body (8a) to pass through is formed in the baffle (7); the loading device comprises an adjustable loading support (2), a fixed pulley (3) on the adjustable loading support (2) and a connecting wire (4) wound around the fixed pulley (3), wherein one end of the connecting wire (4) is connected with an anchor rod, and the other end of the connecting wire is connected with a weight tray (1) for containing weights;
the soil pressure monitoring devices are distributed in the sand-gravel soil for the test in the model box (5) according to a certain arrangement mode.
2. The model test device for the bearing characteristic of the pressure type anchor rod under the action of horizontal load according to claim 1, is characterized in that the connecting line between the rod body (8a) and the fixed pulley (3) is in the horizontal direction, and the connecting line between the fixed pulley (3) and the weight plate (1) is vertically downward.
3. The model test device for the bearing characteristic of the pressure type anchor rod under the action of the horizontal load is characterized in that the adjustable loading bracket (2) comprises a horizontal fixed platform and an adjustable supporting leg below the fixed platform, and the fixed pulley (3) is fixedly arranged on the fixed platform.
4. The model test device for horizontal load pressure type anchor rod load bearing characteristics according to claim 3, wherein the leg comprises an upper structure (2a) and a lower structure (2b), the lower structure (2b) is a hollow structure, and the upper structure (2a) is inserted into the lower hollow structure.
5. The model test device for horizontal load pressure type anchor rod load bearing characteristics according to claim 4, characterized in that the upper structure (2a) and the lower structure (2b) are provided with a plurality of bolt holes, and the upper structure (2a) and the lower structure (2b) are fixedly connected through bolts (2 c).
6. The model test device for load bearing characteristics of a pressure type anchor under horizontal load according to claim 1, wherein the anchor plate (8c) of the pressure type anchor is rectangular.
7. The model test device for the bearing characteristic of the pressure type anchor rod under the action of the horizontal load is characterized in that the base of the dial indicator (9) is connected to a protection device, and the head of the dial indicator is tightly pressed on the top end of the rod body (8 a).
8. The device for testing the bearing characteristic model of the pressure type anchor rod under the action of the horizontal load according to claim 1, wherein the soil pressure monitoring device is a soil pressure gauge (12), and the soil pressure gauge (12) is arranged in a way that: the rod bodies are symmetrically distributed up and down by taking the rod bodies as symmetrical axes.
9. The model test device for the bearing characteristics of the pressure type anchor rod under the action of horizontal load according to claim 1 is characterized in that at least one anchor rod is provided, a plurality of anchor rods are connected into a whole through a loading strip (11), and the loading strip (11) is connected with the top ends of the plurality of anchor rods.
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| CN110344453A (en) * | 2019-07-30 | 2019-10-18 | 山东建筑大学 | Pressure type anchor rod bearer properties model test apparatus and method under horizontal loads |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN110344453A (en) * | 2019-07-30 | 2019-10-18 | 山东建筑大学 | Pressure type anchor rod bearer properties model test apparatus and method under horizontal loads |
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