CN115508069A - Comprehensive evaluation method for dynamic and static mechanical properties of anchor cable - Google Patents
Comprehensive evaluation method for dynamic and static mechanical properties of anchor cable Download PDFInfo
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Abstract
The invention provides a comprehensive evaluation method for dynamic and static mechanical properties of an anchor cable, belonging to the technical field of underground engineering. The comprehensive evaluation method for the dynamic and static mechanical properties of the anchor cable comprises the following steps: prestress value F applied to evaluated anchor cable by anchor cable performance testing device P And obtaining the total elongation eta of the evaluated anchor cable in an experiment I Elastic deformation amount d I And energy absorption rate e I (ii) a Prefabricating rock mass simulation material to manufacture an evaluated combined supporting structure, and performing evaluation combination through an anchor cable performance testing deviceApplied prestress value F of supporting structure P And obtaining the total elongation eta of the evaluated anchor cable in an experiment Ⅱ And an elastic deformation amount d Ⅱ And energy absorption rate e Ⅱ (ii) a And calculating a comprehensive performance evaluation parameter K of the evaluated anchor cable. The comprehensive evaluation method for the dynamic and static mechanical properties of the anchor cable can accurately measure the actual data of the evaluated anchor cable in a dynamic-static coupling state and comprehensively evaluate the comprehensive properties of the evaluated anchor cable.
Description
Technical Field
The invention relates to the technical field of underground engineering, in particular to a comprehensive evaluation method for dynamic and static mechanical properties of an anchor cable.
Background
In recent years, along with the high-speed development of national economy, the development and utilization of underground space are more and more emphasized by the nation, the unprecedented development is achieved in the field of underground engineering, an anchor cable and anchor cable-protective net combined supporting system belongs to a common supporting mode in the underground engineering construction process, and the quality of the performance of an anchor cable is directly related to the construction safety of the underground engineering.
At present, the existing anchor cable performance testing device at home and abroad can only be used for independently measuring the static performance or the dynamic performance of an anchor cable, the anchor cable is often in a dynamic-static coupling state in actual engineering, the existing testing method is difficult to simulate the stress environment of the anchor cable in the actual engineering, and a method for testing the comprehensive performance of an anchor cable-protective net combined supporting system is lacked, so that the comprehensive performance of the anchor cable in the dynamic-static coupling state cannot be accurately measured, and a method for comprehensively evaluating the comprehensive performance of the anchor cable is lacked.
Disclosure of Invention
The invention aims to provide a comprehensive evaluation method for the dynamic and static mechanical properties of an anchor cable, which can accurately measure the actual data of the evaluated anchor cable in a dynamic-static coupling state and comprehensively evaluate the comprehensive properties of the evaluated anchor cable, thereby providing guidance for the design of anchor cable support in underground engineering.
In order to realize the purpose of the invention, the invention adopts the following technical scheme:
according to one aspect of the invention, the invention provides a comprehensive evaluation method for dynamic and static mechanical properties of an anchor cable, which is characterized in that an anchor cable to be evaluated is subjected to a dynamic-static coupling test of the anchor cable through an anchor cable property testing device, a prefabricated combined supporting structure is subjected to a dynamic-static coupling test of the prefabricated combined supporting structure, and a test result is combined to obtain the comprehensive evaluation method, wherein the comprehensive evaluation method for the dynamic and static mechanical properties of the anchor cable comprises the following steps: the anchor cable mechanical property testing device can release an upper drop hammer to impact the anchor cable while applying prestress by performing static tension on the anchor cable through a lower oil cylinder, so as to realize the dynamic-static coupling stress state of the anchor cable; prestressing is applied to the evaluated anchor cable through an anchor cable mechanical property testing deviceForce value F P Performing an anchor cable dynamic-static coupling test to obtain the total elongation eta of the evaluated anchor cable I And an elastic deformation amount d I And energy absorption rate e I (ii) a Prefabricating a rock mass simulation material, prefabricating the rock mass simulation material, the evaluated anchor cable and a net into an evaluated combined supporting structure, and applying a prestress value F to the evaluated combined supporting structure through an anchor cable mechanical property testing device P Performing a dynamic impact test on the anchor cable and the anchor net to obtain the total elongation eta of the evaluated anchor cable in the evaluated combined supporting structure II Elastic deformation amount d II And energy absorption rate e II (ii) a And calculating the comprehensive performance evaluation parameter K of the evaluated anchor cable according to the test results of the anchor cable and the prefabricated combined supporting structure.
According to an embodiment of the present invention, the formula corresponding to the comprehensive performance evaluation parameter K is:
wherein, alpha, beta and gamma are equivalent transformation parameters, and theta is an energy reduction coefficient.
According to an embodiment of the present invention, the anchor cable performance testing apparatus includes a first support, a first hydraulic loading cylinder, a first electromagnetic lock, a first drop hammer and a first laser range finder, the first hydraulic loading cylinder is connected to the bottom of the first support, the top end of the anchor cable to be evaluated is connected to the first support, the bottom end of the anchor cable to be evaluated is connected to the first hydraulic loading cylinder, so as to apply a static load to the anchor cable to be evaluated through the first hydraulic loading cylinder, the first electromagnetic lock is connected to the top of the first support, the first drop hammer is magnetically connected to the first electromagnetic lock, so as to apply a dynamic load to the anchor cable to be evaluated, and the first laser range finder is disposed at the top of the first support, so as to obtain test data of the anchor cable to be evaluated.
According to an embodiment of the invention, the anchor cable mechanical property testing device applies the prestress value F to the anchor cable under evaluation according to the field P-I Performing a dynamic-static coupling test on the anchor cable to obtain the total elongation eta of the evaluated anchor cable I Elastic deformation amount d I And energy absorption rate e I The method comprises the following steps: intercepting a section of the anchor cable to be evaluated with the length L to penetrate into a limiting hole in the top of the first support, wherein the top end of the anchor cable to be evaluated is fixedly connected to the first support through a lock, and the bottom end of the anchor cable to be evaluated is fixed to the first hydraulic loading oil cylinder through the lock; applying a prestress value F to the evaluated anchor cable through the first hydraulic loading oil cylinder P-I Stabilizing the evaluated anchor cable for a period of time; setting the height from the first drop hammer to the bottom end of the anchor cable to be evaluated as h according to test requirements, so that the first drop hammer is released through the first electromagnetic lock to generate impact energy E on the anchor cable to be evaluated I The first laser range finder is used for recording the maximum deformation d of the anchor cable in the impact L (ii) a Repeatedly applying a prestress value F to the evaluated anchor cable through the first hydraulic loading oil cylinder P-I And releasing the first drop hammer through the first electromagnetic lock to generate impact energy E on the evaluated anchor cable I The first laser range finder is used for recording the maximum deformation d of the anchor cable in the impact L Until the anchor cable to be evaluated is broken, obtaining the maximum stretching amount D of the anchor cable to be evaluated through the first laser range finder T-I 。
According to an embodiment of the present invention, the anchor cable performance testing apparatus further includes a second bracket, a tray, a second electromagnetic lock, a second drop hammer, a second hydraulic loading cylinder, a second laser distance meter, and a stress monitor, the tray is disposed at the bottom of the second bracket, the evaluated combined supporting structure is disposed on the tray, the second electromagnetic lock is connected to the top of the second bracket, the second drop hammer is magnetically connected to the second electromagnetic lock, so that the second drop hammer applies a dynamic load to the evaluated combined supporting structure, the second hydraulic loading cylinder is connected to the top of the first bracket, an output end of the second hydraulic loading cylinder is provided with a loading plate, the loading plate abuts against the top surface of the evaluated combined supporting structure, so as to apply a static load to the evaluated combined supporting structure, and the second laser distance meter and the stress monitor are respectively disposed at the top of the second bracket, so as to obtain test data of the evaluated combined supporting structure.
According to an embodiment of the invention, the rock mass simulation material, the evaluated anchor cable and the anchor net are made into an evaluated combined supporting structure, and the anchor cable mechanical property testing device is used for applying a prestress value F to the evaluated combined supporting structure according to the site P Performing a dynamic impact test on the anchor cable and the anchor net to obtain the total elongation eta of the evaluated anchor cable in the evaluated combined supporting structure II Elastic deformation amount d II And energy absorption rate e II The method comprises the following steps: prefabricating the rock mass simulation material according to actual rock mass mechanical parameters on site, drilling the rock mass simulation material according to the row spacing between the anchor cables on site, and placing the rock mass simulation material into the evaluated anchor cable, wherein the anchor net is arranged below the rock mass simulation material and fixedly connected with the evaluated anchor cable and the rock mass simulation material into a whole, the top of the evaluated anchor cable is fixed to the top of the second bracket through a lock, and the rock mass simulation material is fixedly connected to the tray through the lock; the second hydraulic loading oil cylinder and the loading plate are abutted with the evaluated combined supporting structure to apply a prestress value F to the evaluated anchor cable P Setting the height from the second drop hammer to the top end of the evaluated combined supporting structure to be h according to test requirements, and releasing the second drop hammer through the second electromagnetic lock to generate impact energy E on the evaluated combined supporting structure II The second laser range finder is used for recording the maximum deformation d of the anchor cable in the impact L (ii) a Repeating the previous step until the anchor cable to be evaluated is broken, and acquiring the total extension length D of the anchor cable to be evaluated through the second laser range finder T-II 。
According to an embodiment of the invention, wherein the energy absorption rate e is I And the energy absorption rate e II The formula of (1) is:
、
wherein, E T For the total energy produced by the falling weight in the total course of the test, D T-I And D T-II The total extension length of the anchor cable from the original length to the broken anchor cable.
According to an embodiment of the present invention, wherein the total elongation η I And total elongation η II The calculation formula of (2) is as follows:
、
and L is the original length of the anchor cable.
According to an embodiment of the present invention, wherein the elastic deformation amount d is I And the elastic deformation amount d II The calculation formula of (2) is as follows:
、
wherein d is L The maximum deformation of the anchor cable is the maximum deformation of each impact.
One embodiment of the present invention has the following advantages or benefits:
the comprehensive evaluation method for the dynamic and static mechanical properties of the anchor cable can accurately measure the actual data of the evaluated anchor cable in a dynamic-static coupling state, accurately and effectively reflect the impact resistance of the anchor cable in underground engineering or the impact resistance of a combined supporting structure consisting of the anchor cable and an anchor net, and provide important parameter basis for roadway supporting design; the comprehensive performance of the anchor cable is comprehensively evaluated by combining the self performance of the anchor cable and the performance of the combined supporting structure, a multi-angle comprehensive evaluation model is established, and an important basis is provided for the evaluation of the supporting performance of the surrounding rock of the roadway.
Drawings
The above and other features and advantages of the present invention will become more apparent by describing in detail exemplary embodiments thereof with reference to the attached drawings.
Fig. 1 is a schematic diagram illustrating a comprehensive evaluation method for dynamic and static mechanical properties of an anchor cable according to an exemplary embodiment.
Fig. 2 is a schematic diagram illustrating a structure of a dynamic-static coupling test of a cable using a cable performance testing apparatus according to an exemplary embodiment.
Fig. 3 is a schematic diagram illustrating a dynamic-static coupling test of a prefabricated combined supporting structure using a cable bolt performance testing apparatus according to an exemplary embodiment.
Wherein the reference numerals are as follows:
1. an anchor cable to be evaluated; 2. a rock mass simulating material; 3. anchoring the net; 4. a first bracket; 5. a first hydraulic loading cylinder; 6. a first electromagnetic lock; 7. a first drop hammer; 8. a second bracket; 9. a tray; 10. a second electromagnetic lock; 11. a second drop hammer; 12. a second hydraulic loading cylinder; 13. a loading plate; 14. a lock is provided.
Detailed Description
Example embodiments will now be described more fully with reference to the accompanying drawings. Example embodiments may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the concept of example embodiments to those skilled in the art. The same reference numerals in the drawings denote the same or similar structures, and thus a detailed description thereof will be omitted.
The terms "a", "an", "the", "said" are used to indicate the presence of one or more elements/components/etc.; the terms "comprising" and "having" are intended to be inclusive and mean that there may be additional elements/components/etc. other than the listed elements/components/etc.
As shown in fig. 1 to fig. 3, fig. 1 shows a schematic diagram of a comprehensive evaluation method for dynamic and static mechanical properties of an anchor cable provided by the invention. Fig. 2 shows a schematic structural diagram of a dynamic-static coupling test of an anchor cable using an anchor cable performance testing device provided by the invention. Fig. 3 shows a structural schematic diagram of a dynamic-static coupling test for a prefabricated combined supporting structure by using a cable performance testing device provided by the invention.
The embodiment of the invention provides a comprehensive evaluation method for dynamic and static mechanical properties of an anchor cable, which is characterized in that the comprehensive evaluation method for the dynamic and static mechanical properties of the anchor cable comprises the following steps of carrying out a dynamic-static coupling test on the anchor cable 1 to be evaluated through an anchor cable property testing device, carrying out a dynamic-static coupling test on a prefabricated combined supporting structure, and combining the test results to obtain the comprehensive evaluation method, wherein the comprehensive evaluation method for the dynamic and static mechanical properties of the anchor cable comprises the following steps: the anchor cable mechanical property testing device can release an upper drop hammer to impact the anchor cable while applying prestress by performing static tension on the anchor cable through the lower oil cylinder, so as to realize the dynamic-static coupling stress state of the anchor cable; applying prestress value F to evaluated anchor cable 1 through anchor cable mechanical property testing device P Performing an anchor cable dynamic-static coupling test to obtain the total elongation eta of the anchor cable 1 to be evaluated I Elastic deformation amount d I And energy absorption rate e I ；
Prefabricating a rock mass simulation material 2, prefabricating the rock mass simulation material 2, an evaluated anchor cable 1 and an anchor net 3 into an evaluated combined supporting structure, and applying a prestress value F to the evaluated combined supporting structure through an anchor cable mechanical property testing device P Performing a dynamic impact test on the anchor cable and the anchor net to obtain the total elongation eta of the evaluated anchor cable 1 in the evaluated combined supporting structure Ⅱ And an elastic deformation amount d Ⅱ And energy absorption rate e Ⅱ (ii) a And calculating a comprehensive performance evaluation parameter K of the evaluated anchor cable 1 according to the test results of the anchor cable and the prefabricated combined supporting structure.
As shown in fig. 1 to 3, in a first step, the prestress value F to be applied to the anchor cable 1 to be evaluated is determined based on the rock mass simulation material 2 or some other practical situation P After the evaluated anchor cable 1 is connected to the anchor net 3 impact device, a prestress value F is applied to the evaluated anchor cable 1 through a first hydraulic loading oil cylinder 5 P Then, performing an anchor cable dynamic-static coupling test, and generating impact energy E for the evaluated anchor cable 1 according to the test requirements I In the process of the anchor cable dynamic-static coupling test, repeatedly applying impact load to the evaluated anchor cable 1 until the evaluated anchor cable 1 is broken, and measuring the deformation of the evaluated anchor cable 1 through a first laser range finder to obtain the total extension length D of the evaluated anchor cable 1 T-I (ii) a In the second step, the first step is to remove the waste water,reselecting at least three evaluated anchor cables 1, preferably selecting four evaluated anchor cables 1, obtaining a rock mass simulation material 2 from the site, drilling the rock mass simulation material 2 according to the row spacing between the anchor cables on the site and placing the evaluated anchor cables 1, placing an anchor net 3 below the rock mass simulation material 2, fixing the evaluated anchor cables 1, the anchor net 3 and the rock mass simulation material 2 into a whole to form an evaluated combined supporting structure, then installing an impact base plate on the top surface of the rock mass simulation material 2 to play a role in buffering and prevent the rock mass simulation material 2 from moving down greatly to generate large impact on the anchor net 3, then connecting the evaluated combined supporting structure to an anchor cable mechanical property testing device, and applying a prestress value F to the evaluated anchor cables 1 through a second hydraulic loading oil cylinder 12 P Then, performing an anchor cable dynamic-static coupling test, and generating impact energy E for the evaluated anchor cable 1 according to the test requirement I In the process of the anchor cable dynamic-static coupling test, repeatedly applying impact load to the anchor cable 1 to be evaluated until the anchor cable 1 to be evaluated is broken, and measuring the deformation of the four anchor cables 1 to be evaluated through a second laser range finder to obtain the average total extension length D of the four anchor cables 1 to be evaluated T-II (ii) a And thirdly, calculating a comprehensive performance evaluation parameter K of the evaluated anchor cable 1 according to various test data and field data obtained by the anchor cable dynamic-static coupling test, accurately measuring actual data of the evaluated anchor cable 1 in a dynamic-static coupling state by the method, accurately and effectively reflecting the impact resistance of the anchor cable in underground engineering or the impact resistance of a combined supporting structure consisting of the anchor cable and an anchor net, and providing an important parameter basis for roadway supporting design.
In a preferred embodiment of the present invention, the formula corresponding to the comprehensive performance evaluation parameter K is:
wherein, alpha, beta and gamma are equivalent transformation parameters, and theta is an energy reduction coefficient.
As shown in FIG. 1, the value of the overall performance evaluation parameter K is the total elongation eta of the cable 1 under evaluation I Elastic deformation amount d I And energy absorption rate e I And its total elongation eta in the evaluated combined supporting structure II Bullet and bulletAmount of sexual deformation d II And energy absorption rate e II The comprehensive performance of the anchor cable can be comprehensively evaluated by combining the self performance of the anchor cable and the performance of the combined supporting structure, a multi-angle comprehensive evaluation model is established, and an important basis is provided for the evaluation of the supporting performance of the surrounding rock of the roadway. Amount of elastic deformation d I And elastic deformation amount d II The calculation formula of (c) is:
、
wherein d is L The maximum deformation of the anchor cable for each impact.
In a preferred embodiment of the present invention, the anchor cable performance testing apparatus includes a first support 4, a first hydraulic loading cylinder 5, a first electromagnetic lock 6, a first drop hammer 7 and a first laser distance meter, wherein the first hydraulic loading cylinder 5 is connected to the bottom of the first support 4, the top end of the anchor cable 1 to be evaluated is connected to the first support 4, the bottom end of the anchor cable 1 to be evaluated is connected to the first hydraulic loading cylinder 5 so as to apply a static load to the anchor cable 1 to be evaluated through the first hydraulic loading cylinder 5, the first electromagnetic lock 6 is connected to the top of the first support 4, the first drop hammer 7 is magnetically connected to the first electromagnetic lock 6 so as to apply a dynamic load to the anchor cable 1 to be evaluated, and the first laser distance meter is disposed at the top of the first support 4 so as to obtain test data of the anchor cable 1 to be evaluated.
As shown in fig. 2, a cylinder body of a first hydraulic loading cylinder 5 is fixed at the lower part of a first support 4, a first electromagnetic lock 6 is fixed at the upper part of the first support 4, when a test is required, the lower end of an evaluated anchor rope 1 is fixed with a cylinder rod of the first hydraulic loading cylinder 5, so that prestress can be applied to the evaluated anchor rope 1 through the first hydraulic loading cylinder 5, the upper end of the evaluated anchor rope 1 sequentially passes through a first drop hammer 7 and the first electromagnetic lock 6 and then is fixed at the top of the first support 4 through a lock 14, the first electromagnetic lock 6 is electrified to be magnetically attracted with the first drop hammer 7, so that the first drop hammer 7 is fixed with the first electromagnetic lock 6 after being lifted to a predetermined height, the first drop hammer 7 is released after the first electromagnetic lock 6 is powered off during the test, the first drop hammer 7 drops along the evaluated anchor rope 1, so as to apply dynamic load to the lower end of the evaluated anchor rope 1, and a first laser range finder is arranged at the top of the first support 4, so that the irradiation direction of laser is parallel to the evaluated anchor rope 1, thereby more accurately measuring the static load and the static load generated in the process of the evaluated anchor rope 1.
In a preferred embodiment of the invention, the anchor cable 1 to be evaluated is prestressed by the anchor cable mechanical property testing device according to the field P-I Performing an anchor cable dynamic-static coupling test to obtain the total elongation eta of the anchor cable 1 to be evaluated I And an elastic deformation amount d I And energy absorption rate e I The method comprises the following steps: intercepting a section of the anchor cable 1 to be evaluated with the length L, penetrating the anchor cable 1 to be evaluated into a limiting hole at the top of the first support 4, fixedly connecting the top end of the anchor cable 1 to be evaluated to the first support 4 through a lock 14, and fixing the bottom end of the anchor cable 1 to be evaluated to the first hydraulic loading oil cylinder 5 through the lock 14; applying a prestress value F to the evaluated anchor cable 1 through a first hydraulic loading oil cylinder 5 P-I And stabilizing the evaluated anchor cable 1 for a period of time;
setting the height from the first drop hammer 7 to the bottom end of the anchor cable 1 to be evaluated as h according to test requirements so as to release the first drop hammer 7 through the first electromagnetic lock 6 to generate impact energy E on the anchor cable 1 to be evaluated I The maximum deformation d of the anchor cable in the impact is recorded by using a first laser range finder L (ii) a Repeatedly applying a prestress value F to the evaluated anchor cable 1 through the first hydraulic loading oil cylinder 5 P-I And the first electromagnetic lock 6 releases the first drop hammer 7 to generate impact energy E on the evaluated anchor cable 1 I The maximum deformation d of the anchor cable in the impact is recorded by using a first laser range finder L Until the anchor cable 1 to be evaluated is broken, obtaining the maximum stretching amount D of the anchor cable 1 to be evaluated by a first laser range finder T-I 。
As shown in fig. 1 and 2, a section of the anchor cable 1 to be evaluated is cut out to enable the length of the anchor cable 1 to be adapted to the test length L of the anchor cable mechanical property testing device, the upper end of the anchor cable 1 to be evaluated is fixed to the first support 4 through the lock 14 after penetrating through the limiting hole at the top of the first support 4, the lower end of the anchor cable 1 to be evaluated is fixed with the cylinder rod of the first hydraulic loading cylinder 5, and the first hydraulic loading cylinder 5 applies a prestress value F to the anchor cable 1 to be evaluated P Then the height of the first electromagnetic lock 6 is adjusted to make the first lock fallThe height from the hammer 7 to the lower end of the anchor cable 1 to be evaluated after the hammer 7 and the first electromagnetic lock 6 are fixed is h, so that the first drop hammer 7 generates impact energy E to the lower end of the anchor cable 1 to be evaluated when falling down I The first drop hammer 7 is reset and then fixed with the first electromagnetic lock 6, preferably, a reset button and a reset mechanism are arranged on the first support 4, the reset button is operated to enable the reset mechanism to lift the first drop hammer 7 to be fixed with the first electromagnetic lock 6, and the first hydraulic loading oil cylinder 5 is readjusted to apply the prestress value F to the evaluated anchor cable 1 P After the first electromagnetic lock 6 is powered off, the first drop hammer 7 is released to generate impact energy E again for the lower end of the evaluated anchor rope 1 I Repeating the steps until the anchor cable 1 to be evaluated is broken, and measuring by using a first laser range finder to obtain the total extension length D of the anchor cable 1 to be evaluated T-I 。
In a preferred embodiment of the present invention, the anchor cable performance testing apparatus further includes a second bracket 8, a tray 9, a second electromagnetic lock 10, a second drop hammer 11, a second hydraulic loading cylinder 12, a second laser distance meter, and a stress monitor, the tray 9 is disposed at the bottom of the second bracket 8, the joint support structure to be evaluated is disposed on the tray 9, the second electromagnetic lock 10 is connected to the top of the second bracket 8, the second drop hammer 11 is magnetically connected to the second electromagnetic lock 10, so that the second drop hammer 11 applies a dynamic load to the joint support structure to be evaluated, the second hydraulic loading cylinder 12 is connected to the top of the first bracket 4, a loading plate 13 is disposed at an output end of the second hydraulic loading cylinder 12, the loading plate 13 abuts against a top surface of the joint support structure to be evaluated, so as to apply a static load to the joint support structure to be evaluated, and the second laser distance meter and the stress monitor are respectively disposed at the top of the second bracket 8, so as to obtain test data of the joint support structure to be evaluated.
As shown in fig. 3, an evaluated anchor cable 1 in an evaluated combined support structure is fixed on a second support 8, a cylinder body of a second hydraulic loading cylinder 12 is fixed on the upper portion of the second support 8, a cylinder rod of the second hydraulic loading cylinder 12 sequentially passes through a second electromagnetic lock 10 and a second drop hammer 11 from top to bottom and then is fixed with a loading plate 13, the loading plate 13 abuts against the top surface of a rock mass simulation material 2 of the evaluated combined support structure, the lower portion of the evaluated combined support structure is fixed with a tray 9 through a lock, so that the evaluated combined support structure can be fixed on an anchor cable mechanical performance testing device, preferably, an impact backing plate abuts against the top surface of the rock mass simulation material 2, so that the rock mass simulation material 2 is prevented from moving downwards to generate large impact on an anchor net 3, then the evaluated anchor cable 1 is prestressed through the second hydraulic loading cylinder 12 and the loading plate 13, the second electromagnetic lock 10 is energized to enable the second drop hammer 11 to be magnetically attracted with the second drop hammer 11, so that the second drop hammer 11 is fixed with the second drop hammer 10 after the second drop hammer 11 is lifted to a predetermined height, the second drop hammer 1 is tested, the second drop hammer 11 is released after the test, and the second drop hammer 1 is indirectly applied to the laser load simulation material of the anchor cable support 8, thereby the top of the second drop hammer 1, the second drop hammer 8, the second drop hammer 1, the second drop hammer can be more accurately and the laser load measurement device, and the laser load measurement device is indirectly set on the top of the anchor cable 8 in the top of the second drop hammer 8, and the second drop hammer 1, and the second drop hammer 8 in the laser load measurement device, and the top of the second drop hammer 1, and the second drop hammer in the test process.
In a preferred embodiment of the invention, the rock mass simulation material 2, the evaluated anchor cable 1 and the anchor net 3 are made into an evaluated combined supporting structure, and a prestress value F is applied to the evaluated combined supporting structure according to the site through an anchor cable mechanical property testing device P Performing anchor cable-net dynamic impact test to obtain the total elongation eta of the evaluated anchor cable 1 in the evaluated combined supporting structure Ⅱ Elastic deformation amount d Ⅱ And energy absorption rate e Ⅱ The method comprises the following steps: prefabricating a rock mass simulation material 2 according to actual rock mass mechanics parameters on site, drilling the rock mass simulation material 2 according to the row spacing between the anchor cables on site, placing an evaluated anchor cable 1, arranging an anchor net 3 below the rock mass simulation material 2 and fixedly connecting the evaluated anchor cable 1 and the rock mass simulation material 2 into a whole, fixing the top of the evaluated anchor cable 1 to the top of a second bracket 8 through a lock 14, and fixedly connecting the rock mass simulation material 2 to a tray 9 through the lock 14; the second hydraulic loading oil cylinder 12 and the loading plate 13 are abutted with the evaluated combined supporting structure to apply a prestress value F to the evaluated anchor cable 1 P Setting the height from the second drop hammer 11 to the top end of the evaluated combined supporting structure to be h according to the test requirement so as to release the second drop hammer 11 through the second electromagnetic lock 10 to generate impact energy E for the evaluated combined supporting structure II The second laser range finder is used for recording the maximum deformation d of the anchor cable in the impact L (ii) a Repeating the previous step until the anchor cable 1 to be evaluated is broken, and acquiring the total extension length D of the anchor cable 1 to be evaluated through a second laser range finder T-II 。
As shown in fig. 1 and 3, prefabricating a rock mass simulation material 2 according to actual rock mass mechanics parameters on site, preferably prefabricating the rock mass simulation material 2 obtained on site according to the actual rock mass mechanics parameters on site, then selecting at least three evaluated anchor cables 1, preferably four evaluated anchor cables 1 in the application, drilling the rock mass simulation material 2 according to the row spacing between the anchor cables on site, arranging an anchor net 3 below the rock mass simulation material 2, penetrating the evaluated anchor cables 1 through hole sites, fixing the evaluated anchor cables 1, the anchor net 3 and the rock mass simulation material 2 into a whole through a lock or other modes, fixing the lower ends of the evaluated anchor cables 1 with a tray 9, optionally fixing the upper ends of the evaluated anchor cables 1 with a second bracket 8, driving a loading plate 13 to move downwards to abut against the rock mass simulation material 2 by a cylinder rod of a second hydraulic loading cylinder 12, and then applying prestress F to the evaluated combined supporting structure P- Then, the height of the second electromagnetic lock 10 is adjusted to enable the height from the second drop hammer 11 and the second electromagnetic lock 10 to the top surface of the evaluated combined supporting structure to be h after the second drop hammer 11 and the second electromagnetic lock 10 are fixed, so that impact energy E is generated on the evaluated combined supporting structure when the second drop hammer 11 drops II The second drop hammer 11 is reset and then fixed with the second electromagnetic lock 10, preferably, a reset button and a reset mechanism are arranged on the second support 8, the reset button is operated to enable the reset mechanism to lift the second drop hammer 11 to be fixed with the second electromagnetic lock 10, and the second hydraulic loading oil cylinder 12 is readjusted to apply a prestress value F to the evaluated combined supporting structure P After the second electromagnetic lock 10 is powered off, the second drop hammer 11 is released to generate impact energy E again on the top surface of the evaluated combined supporting structure II Repeating the steps until the anchor cable 1 to be evaluated is broken, and measuring by a second laser distance measuring instrument to obtain the total extension length D of the anchor cable 1 to be evaluated T-II And thus can be represented by a formula
、
Calculating the total elongation eta I And total elongation η II And L is the original length of the anchor cable. And by the formula
、
Wherein, E T For the total energy produced by the drop hammer in the total course of the test, D T-I And D T-II The total extension length of the anchor cable from the original length to the broken anchor cable.
The comprehensive evaluation method for the dynamic and static mechanical properties of the anchor cable can accurately measure the actual data of the evaluated anchor cable 1 in a dynamic-static coupling state, accurately and effectively reflect the impact resistance of the anchor cable in underground engineering or the impact resistance of a combined supporting structure consisting of the anchor cable and an anchor net, and provide important parameter basis for roadway supporting design; the comprehensive performance of the anchor cable is comprehensively evaluated by combining the self performance of the anchor cable and the performance of the combined supporting structure, a multi-angle comprehensive evaluation model is established, and an important basis is provided for the evaluation of the supporting performance of the surrounding rock of the roadway.
In embodiments of the present invention, the term "plurality" means two or more unless explicitly defined otherwise. The terms "mounted," "connected," "fixed," and the like are to be construed broadly and include, for example, fixed connections, removable connections, or integral connections. Specific meanings of the above terms in the embodiments of the present invention can be understood by those of ordinary skill in the art according to specific situations.
In the description of the embodiments of the present invention, it should be understood that the terms "upper", "lower", and the like indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience in describing the embodiments of the present invention and simplifying the description, but do not indicate or imply that the referred devices or units must have a specific direction, be configured in a specific orientation, and operate, and thus, should not be construed as limiting the embodiments of the present invention.
In the description herein, the appearances of the phrases "one embodiment," "a preferred embodiment," and similar language, throughout this specification may, but do not necessarily, all refer to the same embodiment or example. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.
The above description is only a preferred embodiment of the present invention, and is not intended to limit the present invention, and various modifications and changes may be made to the present embodiment by those skilled in the art. Any modification, equivalent replacement, improvement and the like made within the spirit and principle of the embodiments of the present invention should be included in the protection scope of the embodiments of the present invention.
Claims (9)
1. A comprehensive evaluation method for dynamic and static mechanical properties of an anchor cable is characterized in that a dynamic-static coupling test of the anchor cable is carried out on an anchor cable (1) to be evaluated through an anchor cable property testing device, a dynamic-static coupling test of a prefabricated combined supporting structure is carried out on the prefabricated combined supporting structure, and the comprehensive evaluation method is obtained by combining a testing result, and the comprehensive evaluation method for the dynamic and static mechanical properties of the anchor cable is characterized by comprising the following steps of:
the anchor cable mechanical property testing device can release an upper drop hammer to impact the anchor cable while applying prestress by performing static tension on the anchor cable through a lower oil cylinder, so as to realize the dynamic-static coupling stress state of the anchor cable;
applying prestress value F to the evaluated anchor cable (1) through the anchor cable mechanical property testing device P Performing an anchor cable dynamic-static coupling test to obtain the total elongation eta of the evaluated anchor cable (1) I Elastic deformation amount d I And energy absorption rate e I ；
Prefabricating a rock mass simulation material (2), prefabricating the rock mass simulation material (2), the evaluated anchor cable (1) and the anchor net (3) into an evaluated combined supporting structureThe mechanical property testing device of the over-anchorage cable applies a prestress value F to the evaluated combined supporting structure P Performing a dynamic impact test on the anchor cable and the anchor net to obtain the total elongation eta of the evaluated anchor cable (1) in the evaluated combined supporting structure Ⅱ Elastic deformation amount d Ⅱ And energy absorption rate e Ⅱ ；
And calculating the comprehensive performance evaluation parameter K of the evaluated anchor cable (1) according to the test results of the anchor cable and the prefabricated combined supporting structure.
2. The anchor cable dynamic and static mechanical property comprehensive evaluation method of claim 1, wherein the calculation formula of the comprehensive property evaluation parameter K is as follows:
wherein, alpha, beta and gamma are equivalent transformation parameters, and theta is an energy reduction coefficient.
3. The anchor cable dynamic and static mechanical property comprehensive evaluation method as claimed in claim 1, wherein the anchor cable performance testing device comprises a first support (4), a first hydraulic loading cylinder (5), a first electromagnetic lock (6), a first drop hammer (7) and a first laser range finder, the first hydraulic loading cylinder (5) is connected to the bottom of the first support (4), the top end of the anchor cable (1) to be evaluated is connected to the first support (4), the bottom end of the anchor cable (1) to be evaluated is connected to the first hydraulic loading cylinder (5) so as to apply a static load to the anchor cable (1) to be evaluated through the first hydraulic loading cylinder (5), the first electromagnetic lock (6) is connected to the top of the first support (4), the first drop hammer (7) is magnetically connected to the first electromagnetic lock (6) so as to apply a dynamic load to the anchor cable (1) to be evaluated, and the first laser range finder is arranged at the top of the first support (4) so as to obtain the test data of the anchor cable (1) to be evaluated.
4. The comprehensive evaluation method of dynamic and static mechanical properties of anchor cable according to claim 3,
the anchor cable mechanical property testing device applies a prestress value F to the evaluated anchor cable (1) according to the field P-I Performing an anchor cable dynamic-static coupling test to obtain the total elongation eta of the evaluated anchor cable (1) I Elastic deformation amount d I And energy absorption rate e I The method comprises the following steps:
intercepting a section of the anchor cable (1) to be evaluated with the length L to penetrate into a limiting hole in the top of the first support (4), wherein the top end of the anchor cable (1) to be evaluated is fixedly connected to the first support (4) through a lock (14), and the bottom end of the anchor cable (1) to be evaluated is fixed to the first hydraulic loading oil cylinder (5) through the lock (14);
applying a prestress value F to the evaluated anchor cable (1) through the first hydraulic loading oil cylinder (5) P-I And stabilizing the evaluated anchor cable (1) for a period of time;
setting the height from the first drop hammer (7) to the bottom end of the cable bolt to be evaluated (1) as h according to test requirements, so as to release the first drop hammer (7) through the first electromagnetic lock (6) to generate impact energy E on the cable bolt to be evaluated (1) I The first laser range finder is used for recording the maximum deformation d of the anchor cable in the impact L ；
Repeatedly applying a prestress value F to the evaluated anchor cable (1) through the first hydraulic loading oil cylinder (5) P-I And the first electromagnetic lock (6) releases the first drop hammer (7) to generate impact energy E on the evaluated anchor cable (1) I The first laser range finder is used for recording the maximum deformation d of the anchor cable in the impact L Until the cable (1) to be evaluated is broken, obtaining the maximum stretching amount D of the cable (1) to be evaluated through the first laser range finder T-I 。
5. The comprehensive evaluation method of dynamic and static mechanical properties of anchor cable according to claim 3,
the anchor cable performance testing device further comprises a second support (8), a tray (9), a second electromagnetic lock (10), a second drop hammer (11), a second hydraulic loading oil cylinder (12), a second laser range finder and a stress monitor, wherein the tray (9) is arranged at the bottom of the second support (8), the evaluated combined supporting structure is arranged on the tray (9), the second electromagnetic lock (10) is connected to the top of the second support (8), the second drop hammer (11) is magnetically connected with the second electromagnetic lock (10), so that the second drop hammer (11) is abutted to the top surface of the evaluated combined supporting structure to apply dynamic load to the evaluated combined supporting structure, the second hydraulic loading oil cylinder (12) is connected to the top of the first support (4), the output end of the second hydraulic loading oil cylinder (12) is provided with a loading plate (13), the loading plate (13) is abutted to the top surface of the evaluated combined supporting structure to apply static load to the evaluated combined supporting structure, and the second laser range finder and the stress monitor are respectively arranged at the top of the second support (8) to obtain the evaluated data of the evaluated combined supporting structure.
6. The comprehensive evaluation method of dynamic and static mechanical properties of anchor cable according to claim 5,
manufacturing the rock mass simulation material (2), the evaluated anchor cable (1) and the anchor net (3) into an evaluated combined supporting structure, and applying a prestress value F to the evaluated combined supporting structure according to the site through the anchor cable mechanical property testing device P Performing an anchor cable-net dynamic impact test to obtain the total elongation eta of the evaluated anchor cable (1) in the evaluated combined supporting structure Ⅱ Elastic deformation amount d Ⅱ And energy absorption rate e Ⅱ The method comprises the following steps:
prefabricating the rock mass simulation material (2) according to actual rock mass mechanical parameters on site, drilling the rock mass simulation material (2) according to the row spacing between the anchor cables on site and placing the rock mass simulation material (2) into the anchor cable (1) to be evaluated, arranging the anchor net (3) below the rock mass simulation material (2) and fixedly connecting the anchor cable (1) to be evaluated and the rock mass simulation material (2) into a whole, fixing the top of the anchor cable (1) to be evaluated at the top of the second bracket (8) through a lock (14), and fixedly connecting the rock mass simulation material (2) to the tray (9) through the lock (14);
the second hydraulic loading oil cylinder (12) and the loading plate (13) are abutted against the evaluated combined supporting structure to apply a prestress value F to the evaluated anchor cable (1) P Setting the height from the second drop hammer (11) to the top end of the evaluated combined supporting structure to be h according to test requirements so as to release the second drop hammer (11) through the second electromagnetic lock (10) to generate impact energy E on the evaluated combined supporting structure II The second laser range finder is used for recording the maximum deformation d of the anchor cable in the impact L ；
Repeating the previous step until the cable to be evaluated (1) is broken, and acquiring the total extension length D of the cable to be evaluated (1) through the second laser range finder T-II 。
7. The comprehensive evaluation method for dynamic and static mechanical properties of anchor cable according to claim 2, wherein the energy absorption rate e is I And said energy absorption rate e II The formula of (1) is:
wherein E is T For the total energy produced by the drop hammer in the total course of the test, D T-I And D T-II The total extension length of the anchor cable from the original length to the broken anchor cable.
8. The comprehensive evaluation method for dynamic and static mechanical properties of anchor cables as claimed in claim 2, wherein the total elongation η is I And total elongation eta II The calculation formula of (c) is:
wherein L is the original length of the anchor cable.
9. The comprehensive evaluation method of dynamic and static mechanical properties of anchor cable according to claim 2, wherein the elastic deformation d I And the elastic deformation amount d II The calculation formula of (c) is:
wherein d is L The maximum deformation of the anchor cable for each impact.
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| CN115796456A (en) * | 2023-01-29 | 2023-03-14 | 中国矿业大学(北京) | Stability evaluation and control method for underground engineering surrounding rock under complex conditions |
| CN118310899A (en) * | 2024-04-09 | 2024-07-09 | 山东大学 | Device and method for testing static stretching and dynamic impact performance of energy-absorbing supporting structure |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115796456A (en) * | 2023-01-29 | 2023-03-14 | 中国矿业大学(北京) | Stability evaluation and control method for underground engineering surrounding rock under complex conditions |
| CN118310899A (en) * | 2024-04-09 | 2024-07-09 | 山东大学 | Device and method for testing static stretching and dynamic impact performance of energy-absorbing supporting structure |
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