CN105931558B - Roadway excavation and unloading simulation test device and test method - Google Patents

Abstract

The present invention proposes a kind of roadway excavation unloading model experimental rig and test method, in roadway excavation unloading model experimental rig, lower bearing plate, side bearing plate and upper bearing plate wrap up sample jointly, prefabricated tunnel is offered in sample, outer surface along prefabricated tunnel is equipped with fixed plate, it is opened up in fixed plate fluted, pressure sensor is provided in groove, pressure sensor is connect with Computer signal, one end of support rod and one end of unloader lever are hinged, the other end of support rod is flexibly connected with groove and the other end of support rod is close to pressure sensor, loading end acts on side bearing plate, upper bearing plate and loading end is connect with Computer signal.The invention has the benefit that can simulate roadway surrounding rock excavates unloading process, significantly additional disturbance will not be caused to country rock, accurately controls the unloding speed and off-load amount of country rock, the accurate related mechanics parameter for measuring country rock in unloading process.

Description

Roadway excavation and unloading simulation test device and test method

technical field

The invention relates to the technical field of underground engineering excavation, in particular to a simulation test device and a test method for roadway excavation and unloading.

Background technique

The excavation of underground engineering is actually the release of the stress on a certain side of the rock mass, which destroys the original mechanical equilibrium state, causing new deformation of the rock mass, or even fracture and fragmentation, that is, the deformation and damage of the surrounding rock of the roadway in the underground engineering. It is caused by the unloading of the surrounding rock. Therefore, the research on the excavation and unloading of the surrounding rock of the roadway is of great significance to further explore the deformation and failure mechanism of the surrounding rock of the roadway and the control technology of the stability of the surrounding rock of the roadway. At present, the methods used to simulate roadway excavation and unloading mainly include pre-buried method and non-pre-buried method. The pre-embedded method refers to pre-embedding the roadway excavation device into the sample in the process of making the simulated sample. The pre-embedded method means that in the process of making the simulated sample, the roadway excavation device is not pre-buried, and the artificial or mechanical method is directly used for excavation at the roadway position to realize the simulation of roadway excavation and unloading. Obviously, the non-buried method is more in line with engineering practice in form, but there are obvious shortcomings. For example, during the simulated excavation process, it will cause obvious additional disturbance to the surrounding rock, and it is difficult to specifically study the excavation unloading effect. Although there are certain differences in form and engineering practice, the embedded method has significant advantages over the non-embedded method. First, the pre-embedded device can be reused to reduce the experimental cost. Secondly, the simulation of roadway excavation using the embedded method can control the excavation process and speed. However, the existing technology is difficult to accurately control the process of simulated excavation and unloading of the roadway, and cannot better reflect the mechanical characteristics of the deformation and failure of the surrounding rock on site during the unloading process.

The Chinese patent document with the publication number CN103745646B discloses a test device for simulating roadway excavation, unloading and support. The device is composed of a mandrel, a steel ball, a force transmission pipe and a support pipe. The excavation and unloading process of the roadway is simulated by extracting the mandrel, but it is impossible to accurately control the unloading rate of the surrounding rock and accurately measure the force during the unloading process of the surrounding rock, that is, it cannot reflect the deformation, damage and excavation of the surrounding rock. The specific relationship between the unloading parameters. The Chinese patent document with publication number CN104833569A discloses an excavation and unloading device suitable for geomechanical model tests, which is a non-pre-embedded method to simulate roadway excavation and unloading. The rock blocks are drilled to simulate the excavation process, but during the excavation process, it will cause obvious additional disturbance to the surrounding rock, and it is difficult to specifically study the excavation unloading effect. The Chinese patent document with publication number CN105277673A discloses a method for simulating excavation and unloading to cause strain-type rock bursts in roadways. The method first makes rock samples into regular shapes, and then drills holes in the center of the front and back of the observation surface. The circular through hole is extracted to simulate the roadway, and the concrete column is filled in the circular through hole. Finally, the excavation process of the roadway is simulated by poking out the middle concrete column. related mechanical parameters of rock.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a roadway excavation and unloading simulation test device and a test method, which are used to simulate the roadway surrounding rock excavation and unloading process, which will not cause obvious additional disturbance to the surrounding rock, and can accurately control the unloading of the surrounding rock. The loading rate and unloading amount, and the relevant mechanical parameters of the surrounding rock during the unloading process are accurately measured.

The invention provides a simulation test device for roadway excavation and unloading, which includes a pressure bearing plate, a sample, a fixed plate, a pressure sensor, a support rod, an unloading rod, a loading end and a computer. The pressure-bearing plate, the upper pressure-bearing plate, the lower pressure-bearing plate, the side pressure-bearing plate and the upper pressure-bearing plate jointly wrap the sample, a prefabricated roadway is opened in the sample, and a fixed plate is laid along the outer surface of the prefabricated roadway. There is a groove, a pressure sensor is arranged in the groove, the pressure sensor is connected with the computer signal, one end of the support rod is hinged with one end of the unloading rod, the other end of the support rod is movably connected with the groove, and the other end of the support rod is close to For the pressure sensor, the loading end acts on the side bearing plate and the upper bearing plate, and the loading end is connected with the computer signal.

Further, one end of the support rod is fixedly connected with a hinge rod, and one end of the unloading rod is provided with a T-shaped groove including a horizontal groove and a vertical groove, and the extending direction of the horizontal groove to both sides is perpendicular to the axis direction of the unloading rod, and the vertical direction is vertical. The extending direction of the groove to one side is parallel to the axial direction of the unloading rod, the two ends of the hinge rod are hinged with the two ends of the horizontal groove of the T-shaped groove, and the support rod can rotate along the extending direction of the vertical groove to one side.

Further, the extension direction of the vertical groove to one side is opposite to the direction of the unloading rod from one end to the other end.

Further, there are four supporting rods and four fixing plates, one end of the four supporting rods is hinged with one end of the unloading rod respectively, and the other ends of the four supporting rods are respectively movably connected with the grooves on the four fixing plates.

Further, one end of the unloading rod is fixedly connected with the installation end, and one end of the support rod is hinged with the installation end.

Further, the fixing plate is provided with a groove in the middle position of the fixing plate.

Further, the shape and outline of the prefabricated roadway is cylindrical, and the shape of the fixing plate is an arc that fits with the outer surface of the cylindrical prefabricated roadway.

Further, the support rod and the unloading rod are made of high-strength steel.

Further, the bearing plate is made of solid steel plate.

The present invention also provides a simulation test method for roadway excavation and unloading, using the above-mentioned roadway excavation and unloading simulation test device, comprising the following steps:

Step 1: Prepare a sample, and set up a prefabricated roadway in the sample to ensure that the size of the prefabricated roadway matches the size of the fixed plate;

Step 2: Place the prepared sample on the lower bearing plate, and attach the side bearing plate and the upper bearing plate to the outer surface of the sample, so that the lower bearing plate, the side bearing plate and the upper bearing plate The pressure plate co-wrapped the sample;

Step 3. Place the fixed plate in the prefabricated tunnel in the sample, insert the other end of the support rod into the groove of the fixed plate to be movably connected with the groove, and the other end of the support rod is close to the pressure sensor to keep the support rod. The axis is perpendicular to the axis of the prefabricated roadway;

Step 4: The computer controls the loading end to apply lateral stress and axial stress to the side bearing plate and the upper bearing plate respectively, until the stress value monitored by the pressure sensor meets the test requirements;

Step 5. Keep the lateral stress and the axial stress as constant values, pull out the other end of the unloading rod so that the unloading rod is pulled out at a certain speed along the axial direction of the unloading rod, so that the support rod is gradually inclined to achieve For the purpose of unloading, the stress value of the pressure sensor is monitored and recorded in real time through the computer.

Compared with the prior art, the tunnel excavation and unloading simulation test device and the test method of the present invention have the following characteristics and advantages:

1. The tunnel excavation and unloading simulation test device of the present invention has an ingenious structure design, which can simulate the excavation and unloading process of the surrounding rock of the tunnel, without causing obvious additional disturbance to the surrounding rock, and can accurately control the unloading rate and Unloading amount and accurate measurement of relevant mechanical parameters of surrounding rock during the unloading process;

2. The tunnel excavation and unloading simulation test method of the present invention will not cause obvious additional disturbance to the surrounding rock during the excavation and unloading process of the simulated tunnel surrounding rock, and the surrounding rock can be accurately controlled by controlling the axial movement rate of the unloading rod During the axial movement of the unloading rod, a certain angle is formed between the support rod and the vertical plane, and the unloading amount of the surrounding rock is precisely controlled. During the unloading process, the pressure sensor accurately measures the surrounding rock during the unloading process. related mechanical parameters.

The features and advantages of the present invention will become more apparent after reading the detailed description of the present invention in conjunction with the accompanying drawings.

Description of drawings

In order to illustrate the embodiments of the present invention or the technical solutions in the prior art more clearly, the following briefly introduces the accompanying drawings that need to be used in the description of the embodiments or the prior art. Obviously, the drawings in the following description are For some embodiments of the present invention, for those of ordinary skill in the art, other drawings can also be obtained according to these drawings without creative efforts.

Fig. 1 is the structural representation of the tunnel excavation unloading simulation test device in the embodiment of the present invention;

2 is a cross-sectional view of a support rod, a hinge rod and an unloading rod in the tunnel excavation unloading simulation test device in the embodiment of the present invention;

Fig. 3 is A-A sectional view in Fig. 2 in the embodiment of the present invention;

Fig. 4 is the top view of the support rod, the hinge rod and the unloading rod in the roadway excavation unloading simulation test device in the embodiment of the present invention;

in,

11, lower bearing plate, 12, side bearing plate, 13, upper bearing plate, 2, sample, 3, fixing plate, 31, groove, 41, support rod, 42, hinge rod, 43, unloading Rod, 431, T-slot, 5, pressure sensor, 6, prefabricated roadway, 7, signal cable, 8, computer.

Detailed ways

As shown in Figures 1 to 4, this embodiment provides a simulation test device for roadway excavation and unloading. Sample 2, the sample 2 is provided with a cylindrical prefabricated roadway 6, and a fixed plate 3 is laid along the outer surface of the prefabricated roadway 6, and the shape of the fixed plate 3 is the same as that of the cylindrical prefabricated roadway 6. Arc that fits the outer surface. Of course, the shape and outline of the prefabricated roadway 6 can also be other shapes, for example, the cross-section of the prefabricated roadway 6 is a rectangular cylindrical shape. Designing the prefabricated roadway 6 into a cylindrical shape facilitates the opening of the prefabricated roadway 6 during the test, and also facilitates the quick assembly of the arc-shaped fixing plate 3 into the prefabricated roadway 6 during the test, thereby improving the test efficiency. A groove 31 is opened in the middle position of the fixing plate 3, and a pressure sensor 5 is arranged in the groove 31. The pressure sensor 5 is connected with the computer 8 by a signal cable 7, and one end of a support rod 41 made of high-strength steel is fixedly connected. There is a hinged rod 42, one end of the unloading rod 43 made of high-strength steel is fixedly connected with a mounting end, and the mounting end is provided with a T-shaped groove 431 including a horizontal groove and a vertical groove. The axial direction of the unloading rod 43 is vertical, the extension direction of the vertical groove to one side is parallel to the axial direction of the unloading rod 43, and the extending direction of the vertical groove to one side is opposite to the direction of the unloading rod 43 from one end to the other end, hinged The two ends of the rod 42 are hinged with the two ends of the horizontal groove of the T-shaped groove 431 respectively. The support rod 41 can rotate along the extension direction of the vertical groove to one side. The other end of 41 is in close contact with the pressure sensor 5 , the loading end acts on the side bearing plate 12 and the upper bearing plate 13 , and the loading end is signally connected to the computer 8 via the signal cable 7 . In the above-mentioned roadway excavation and unloading simulation test device in this embodiment, there are four support rods 41 and four fixing plates 3, and one end of the four support rods 41 is fixedly connected to four hinge rods 42 and four hinge rods respectively. 42 are respectively hinged with the installation end of one end of the unloading rod 43 , and the other ends of the four support rods 41 are respectively movably connected with the grooves 31 on the four fixing plates 3 .

The above-mentioned simulation test device for unloading of roadway excavation in this embodiment, on the basis that the computer 8 controls the loading end to exert stress on the side bearing plate 12 and the upper bearing plate 13, along the "unloading" as shown in Figure 4 The unloading rod 43 is pulled in the direction of ”, and the pulling of the unloading rod 43 drives the support rod 41 to form an angle with the vertical plane, thereby realizing the excavation and unloading process of the simulated roadway surrounding rock. During the unloading process, there is no obvious additional disturbance to the surrounding rock; in the above-mentioned simulated roadway surrounding rock excavation and unloading process, the unloading rate of the surrounding rock is precisely controlled by controlling the axial movement rate of the unloading rod 43 to achieve graded unloading. , during the axial movement of the unloading rod 43, the support rod 41 forms a certain angle with the vertical plane, so that the stress acting on the sample 2 by the support rod gradually becomes smaller, and the supporting strength of the surrounding rock of the roadway is quantitatively reduced. Thereby, the unloading amount of the surrounding rock is precisely controlled, and the pressure sensor 5 accurately measures the relevant mechanical parameters of the surrounding rock during the unloading process of the simulated roadway surrounding rock excavation and unloading, and monitors and records it in real time through the computer 8 . It should be noted that the extension direction of the vertical groove of the T-shaped groove 431 to one side is opposite to the direction of the unloading rod 43 from one end to the other end (ie, the “unloading” direction shown in FIG. 4 ). When the unloading rod 43 is unloaded, the support rod 41 can only rotate in the opposite direction to the "unloading" direction, so that in the initial stage of simulating the unloading of roadway excavation, it is convenient to fix the unloading rod 43 to fix the support rod 41, so that the The axis of the support rod 41 is perpendicular to the axis of the prefabricated roadway 6 (the axis of the unloading rod 43); when the unloading rod 43 is drawn, the contact between the support rod 41 and the unloading rod 43 is avoided, so that the simulated roadway surrounding rock excavation and unloading process is more precise.

The present invention also provides a simulation test method for roadway excavation and unloading, using the above-mentioned roadway excavation and unloading simulation test device, comprising the following steps:

Step 1, prepare sample 2, set prefabricated roadway 6 in sample 2, ensure that the size of prefabricated roadway 6 matches the size of fixed plate 3;

Step 2: Place the prepared sample 2 on the lower bearing plate 11, and attach the side bearing plate 12 and the upper bearing plate 13 to the outer surface of the sample 2, so that the lower bearing plate 11, the side bearing The pressure-bearing plate 12 and the upper pressure-bearing plate 13 jointly wrap the sample 2;

Step 3. Place the fixing plate 3 in the prefabricated roadway 6 in the sample 2, insert the other end of the support rod 41 into the groove 31 of the fixing plate 3 to be movably connected with the groove 31, and the other end of the support rod 41 is tightened. Paste the pressure sensor 5, and keep the axis of the support rod 41 perpendicular to the axis of the prefabricated roadway 6;

Step 4: The computer 8 controls the loading end to apply lateral stress and axial stress to the side bearing plate 12 and the upper bearing plate 13 respectively, until the stress value monitored by the pressure sensor 5 meets the test requirements;

Step 5. Keep the lateral stress and the axial stress as constant values, pull the other end of the unloading rod 43 so that the unloading rod 43 is pulled out at a certain speed along the axial direction of the unloading rod 43, so that the support rod 41 is pulled out. It is gradually inclined to achieve the purpose of unloading, and the stress value of the pressure sensor 5 is monitored and recorded in real time through the computer 8 .

Step 6: After the test, save the data in the computer 8 for use.

The above-mentioned roadway excavation and unloading simulation test method in this embodiment will not cause obvious additional disturbance to the surrounding rock during the excavation and unloading process of the simulated roadway surrounding rock. To accurately control the unloading rate of the surrounding rock, the axial movement of the unloading rod 43 drives the rotation of the support rod 41, so that the support rod 41 forms a certain angle with the vertical plane, so that the supporting strength of the surrounding rock of the roadway is quantitative. It is beneficial to observe and record the relationship between the unloading rate, the unloading amount and the deformation and failure characteristics of the surrounding rock. During the unloading process, the pressure sensor 5 can accurately measure the relevant mechanical parameters of the surrounding rock during the unloading process. Variation characteristics of surrounding rock stress.

Of course, the above description is not intended to limit the present invention, and the present invention is not limited to the above examples. Changes, modifications, additions or substitutions made by those skilled in the art within the essential scope of the present invention should also belong to the present invention. the scope of protection of the invention.

Claims (8)

1. The utility model provides a tunnel excavation off-load analogue test device which characterized in that: the device comprises a bearing plate, a sample, a fixing plate, a pressure sensor, a support rod, a load unloading rod, a loading end and a computer, wherein the bearing plate comprises a lower bearing plate, a side bearing plate and an upper bearing plate, the lower bearing plate, the side bearing plate and the upper bearing plate jointly wrap the sample, a prefabricated tunnel is arranged in the sample, the fixing plate is laid along the outer surface of the prefabricated tunnel, a groove is formed in the middle of the fixing plate on the fixing plate, the pressure sensor is arranged in the groove and is in signal connection with the computer, a hinge rod is fixedly connected to one end of the support rod, a T-shaped groove comprising a transverse groove and a vertical groove is formed in one end of the load unloading rod, the extending direction of the transverse groove to two sides is perpendicular to the axial direction of the load unloading rod, the extending direction of the vertical groove to one side is parallel to the axial direction of the load unloading rod, two ends of the hinge rod are respectively hinged to two ends of the transverse, the other end of the supporting rod is movably connected with the groove, the other end of the supporting rod is tightly attached to the pressure sensor, the loading end acts on the side bearing plate and the upper bearing plate, and the loading end is connected with a computer signal.

2. The roadway excavation unloading simulation test device according to claim 1, characterized in that: the vertical groove extends to one side in the direction opposite to the direction from one end to the other end of the unloading rod.

3. The roadway excavation unloading simulation test device according to any one of claims 1 to 2, characterized in that: the number of the supporting rods is four, the number of the fixing plates is four, one end of each supporting rod is hinged with one end of the load unloading rod, and the other end of each supporting rod is movably connected with the groove in each fixing plate.

4. The roadway excavation unloading simulation test device according to any one of claims 1 to 2, characterized in that: one end of the unloading rod is fixedly connected with a mounting end, and one end of the supporting rod is hinged with the mounting end.

5. The roadway excavation unloading simulation test device according to any one of claims 1 to 2, characterized in that: the shape profile of the prefabricated tunnel is cylindrical, and the shape of the fixing plate is an arc shape which is attached to the outer surface of the cylindrical prefabricated tunnel.

6. The roadway excavation unloading simulation test device according to any one of claims 1 to 2, characterized in that: the support rod and the load-unloading rod are made of high-strength steel.

7. The roadway excavation unloading simulation test device according to any one of claims 1 to 2, characterized in that: the bearing plate is made of a solid steel plate.

8. A tunnel excavation unloading simulation test method applying the tunnel excavation unloading simulation test device of any one of claims 1 to 7, characterized by comprising the following steps:

preparing a sample, wherein a prefabricated roadway is arranged in the sample, and the size of the prefabricated roadway is ensured to be matched with that of a fixed plate;

placing the prepared sample on a lower pressure bearing plate, and attaching a side pressure bearing plate and an upper pressure bearing plate to the outer surface of the sample so as to enable the lower pressure bearing plate, the side pressure bearing plate and the upper pressure bearing plate to jointly wrap the sample;

placing the fixing plate in a prefabricated roadway in the sample, inserting the other end of the supporting rod into a groove of the fixing plate to be movably connected with the groove, enabling the other end of the supporting rod to be tightly attached to the pressure sensor, and keeping the axis of the supporting rod vertical to the axis of the prefabricated roadway;

step four, the computer controls the loading end to respectively apply lateral stress and axial stress to the side bearing plate and the upper bearing plate until the stress value monitored by the pressure sensor reaches the test requirement;

and fifthly, keeping the lateral stress and the axial stress as fixed values, pulling the other end of the unloading rod to ensure that the unloading rod is pulled outwards at a certain speed along the axial direction of the unloading rod, gradually inclining the supporting rod to achieve the unloading purpose, and monitoring and recording the stress value of the pressure sensor in real time through a computer.