Pressure head fastening device for rock stress path simulation test

Abstract

The invention discloses a rock stress path simulation test pressure head fastening device. The rock stress path simulation test pressure head fastening device comprises a pressure head, an inner fastening piece and a plurality of outer fastening pieces, a square groove is formed in the center of the upper end face of the pressing head. The inner fastener is positioned below the pressure head and is fixedly connected with the pressure head; the plurality of outer fasteners are uniformly distributed on the periphery of the pressure head, and the plurality of outer fasteners are detachably connected with the outer side wall of the pressure head; wherein the pressing head and the inner fastening piece are both of a cylindrical structure, the central axis of the inner fastening piece and the central axis of the pressing head are located on the same straight line, and the other end of the inner fastening piece enters the interior of one end of the hollow cylinder sample and makes contact with the inner side wall of the hollow cylinder sample. Compared with the prior art, the rock stress path simulation test pressure head fastening device has the advantages of fixing a hollow cylinder sample, monitoring the thickness of the sample, being wide in applicable sample size and the like.

Description

Technical Field

[0001] The invention relates to the technical field of mechanical testing, and in particular to a rock stress path simulation test pressure head fastening device. Background Art

[0002] Hydropower development requires the construction of a large number of deep underground projects. Most of these projects are located in high-stress complex strata. The excavation of large underground projects under high stress will cause strong disturbances to the surrounding rock, resulting in complex changes in the stress state of the surrounding rock. The prominent feature is that the change in the value of the principal stress is accompanied by the rotation of the stress principal axis.

[0003] Among the existing rock mechanics test instruments, there is a patent that discloses a pressure-feed horizontal directional drilling engineering geological survey hydraulic fracturing test device. This patent can simulate the complex stress path of rock, but in the process of torque application, there is a problem of uneven force on the sample, resulting in the inability to transmit torque to the entire hollow cylindrical sample. There is also a patent that discloses a rock hollow cylindrical torsion shear instrument and a torque application device, which includes: a lower pressure head, an upper pressure head, a force transmission shaft group, a power component, a torque sensor and a torque controller. This patent has developed a new torque application technology that has no relative freedom with the rock specimen and can transmit torque. A special strong rigid glue is used to bond the end face of the rock specimen and the upper and lower pressure heads to meet the strength requirements for applying torque. However, this scheme is greatly affected by human factors. It is easy to have loose bonding during the bonding process, resulting in torque transmission loss and error. When using rock specimens of different sizes for torsion tests, it is necessary to prepare multiple types of upper and lower pressure heads, which increases the cost of the experiment.

[0004] Therefore, how to provide a rock stress path simulation test pressure head fastening device so that it can achieve the technical effect of solving the torque application in the rock stress path simulation test is a technical problem that technical personnel in this field urgently need to solve. Summary of the invention

[0005] In view of some problems existing in the prior art, the technical problem to be solved by the present invention is to provide a rock stress path simulation test head fastening device to fix the rock sample and solve the technical problem of torque application in the rock stress path simulation test.

[0006] To achieve the above-mentioned purpose, the present invention provides a rock stress path simulation test pressure head fastening device, the rock stress path simulation test pressure head fastening device comprising: a pressure head, a square groove is arranged at the center of the upper end surface of the pressure head; an inner fastener, the inner fastener is located below the pressure head, one end of the inner fastener is fixedly connected to the lower end surface of the pressure head; a plurality of outer fasteners, a plurality of the outer fasteners are evenly arranged on the periphery of the pressure head, and a plurality of the outer fasteners are detachably connected to the outer side wall of the pressure head; wherein, the pressure head is a cylindrical structure, the inner fastener is a cylindrical structure, the inner fastener and the central axis of the pressure head are located on the same straight line, and the other end of the inner fastener enters into one end of the hollow cylindrical sample and contacts the inner side wall of the hollow cylindrical sample.

[0007] In the first aspect, each of the external fasteners includes: an arc-shaped panel, the center of which is located on the central axis of the pressing head, and the central angle of the arc-shaped panel is 45°; a first driving hole and a second driving hole are opened at the midline position of the arc-shaped panel along the radial direction of the pressing head, and the second driving hole is located directly below the first driving hole.

[0008] In the first aspect, the first drive hole and the second drive hole are both threaded holes.

[0009] In the first aspect, a plurality of press head threaded holes are evenly distributed on the outer side wall of the press head, and a plurality of the press head threaded holes have a plurality of the first driving holes matched with the number thereof, and each of the press head threaded holes is matched with the position of a corresponding one of the first driving holes.

[0010] In the first aspect, each of the external fasteners also includes: an upper drive rod, one end of which is a threaded structure, one end of which passes through the first drive hole and enters the corresponding press head threaded hole, and is threadedly connected to the curved panel and the outer side wall of the press head in turn.

[0011] In the first aspect, each of the external fasteners further includes: a lower driving rod, one end of which is a threaded structure, one end of which passes through the second driving hole and abuts against the outer wall of the hollow cylindrical specimen, and the lower driving rod is threadedly connected to the arc panel; wherein the maximum distance between the arc panel and the inner fastener in the radial direction of the inner fastener is less than the length of the threaded structure at one end of the lower driving rod.

[0012] In the first aspect, each of the press head threaded holes is disposed in the press head and extends in a radial direction of the press head.

[0013] In the first aspect, the number of the outer fasteners is four.

[0014] In the first aspect, the rock stress path simulation test head fastening device also includes: a plurality of displacement sensors, the number of the plurality of displacement sensors being adapted to the number of the plurality of external fasteners, and each of the displacement sensors being arranged at the other end of a corresponding one of the lower driving rods.

[0015] In the first aspect, the rock stress path simulation test pressure head fastening device also includes: four anti-slip washers, the first anti-slip washer passes through the inner fastener and is arranged on the lower end surface of the pressure head, the second anti-slip washer is arranged on the inner side of the arc panel in close contact with the arc panel; the third anti-slip washer is arranged on one end of the lower driving rod, and the fourth anti-slip washer is arranged on the outer side wall of the inner fastener.

[0016] Beneficial effects:

[0017] In the present application, the square groove arranged in the center of the upper end face of the pressure head serves to connect and combine the torque transmission mechanism, so as to apply torque to the hollow cylindrical sample in the rock stress path simulation test pressure head fastening device of the present application through the torque transmission mechanism; the inner fastener is a cylindrical structure, and the inner wall of the hollow cylinder can be made to stick to the outer wall of the inner fastener through the hollow adaptation of the cylinder and the hollow cylindrical sample, thereby playing a preliminary fixing role for the hollow cylinder; a number of outer fasteners are evenly arranged on the periphery of the pressure head, and the outer fasteners are detachably connected to the pressure head. After the hollow cylindrical sample is mounted on the inner fastener, the distance between the outer fastener and the inner fastener is adjusted so that the outer fastener is against the outer wall of the hollow cylindrical sample to further fix the hollow cylindrical sample. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of this specification or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0019] Figure 1 It is a structural schematic diagram of a rock stress path simulation test pressure head fastening device of the present invention;

[0020] Figure 2 It is a front view of a rock stress path simulation test pressure head fastening device of the present invention;

[0021] Figure 3 It is a side view of a rock stress path simulation test pressure head fastening device of the present invention;

[0022] Figure 4It is a top view of a rock stress path simulation test pressure head fastening device of the present invention.

[0023] Reference numerals:

[0024] 1. Press head; 2. Square groove; 3. Inner fastener; 4. Outer fastener; 41. Curved panel; 42. Upper driving rod; 43. Lower driving rod; 5. Displacement sensor. DETAILED DESCRIPTION

[0025] The following will be combined with the drawings in the embodiments of this specification to clearly and completely describe the technical solutions in the embodiments of this specification. Obviously, the described embodiments are only part of the embodiments of this specification, not all of the embodiments. Based on the embodiments in this specification, all other embodiments obtained by ordinary technicians in this field belong to the scope of protection of the present invention.

[0026] Embodiment 1

[0027] like Figures 1 to 4 As shown, the first embodiment provides a rock stress path simulation test pressure head fastening device, and the rock stress path simulation test pressure head fastening device comprises: a pressure head 1, a square groove 2 is arranged at the center of the upper end surface of the pressure head 1; an inner fastener 3, the inner fastener 3 is located below the pressure head 1, and one end of the inner fastener 3 is fixedly connected to the lower end surface of the pressure head 1; a plurality of outer fasteners 4, a plurality of the outer fasteners 4 are evenly arranged on the periphery of the pressure head 1, and a plurality of the outer fasteners 4 are detachably connected to the outer side wall of the pressure head 1; wherein, the pressure head 1 is a cylindrical structure, the inner fastener 3 is a cylindrical structure, the inner fastener 3 and the central axis of the pressure head 1 are located on the same straight line, and the other end of the inner fastener 3 enters into one end of the hollow cylindrical specimen and contacts the inner side wall of the hollow cylindrical specimen.

[0028] In the present application, the square groove arranged in the center of the upper end face of the pressure head serves to connect and combine the torque transmission mechanism, so as to apply torque to the hollow cylindrical sample in the rock stress path simulation test pressure head fastening device of the present application through the torque transmission mechanism; the inner fastener is a cylindrical structure, and the inner wall of the hollow cylinder can be made to stick to the outer wall of the inner fastener through the hollow adaptation of the cylinder and the hollow cylindrical sample, thereby playing a preliminary fixing role for the hollow cylinder; a number of outer fasteners are evenly arranged on the periphery of the pressure head, and the outer fasteners are detachably connected to the pressure head. After the hollow cylindrical sample is mounted on the inner fastener, the distance between the outer fastener and the inner fastener is adjusted so that the outer fastener is against the outer wall of the hollow cylindrical sample to further fix the hollow cylindrical sample.

[0029] In some possible implementations, each of the external fasteners 4 includes: an arc-shaped panel 41, the center of which is located on the central axis of the ram 1, and the central angle of the arc-shaped panel 41 is 45°; a first driving hole and a second driving hole along the radial direction of the ram are opened at the midline position of the arc-shaped panel 41, and the second driving hole is located directly below the first driving hole; the first driving hole and the second driving hole are both threaded holes; a plurality of ram threaded holes are evenly distributed on the outer side wall of the ram 1, and a plurality of the ram threaded holes have a plurality of the first driving holes matched with the number thereof, and each of the ram threaded holes is matched with the position of a corresponding one of the first driving holes.

[0030] Specifically, the arc panel is connected to the pressure head through an upper driving rod, the length of the threaded end of the upper driving rod is greater than the length of the pressure head threaded hole of the pressure head, and the corresponding center of the arc panel is 45°, so that the arc panels are symmetrically distributed in pairs around the periphery of the pressure head. At the same time, the corresponding center angle is 45°, which expands the size range of applicable hollow cylindrical specimens and reduces costs; the pressure head threaded hole, the first driving hole and the second driving hole are all arranged along the radial direction of the pressure head, so that the upper driving rod and the lower driving rod are in a parallel relationship; the subsequent upper driving rod and the lower driving rod are spirally moved along the radial direction of the pressure head, so that the upper driving rod is fixedly connected to the outer side wall of the pressure head, and because it is a threaded connection, the upper driving rod and the pressure head are detachably connected; the subsequent lower driving rod can be spirally moved along the radial direction of the pressure head, so that the lower driving rod can better resist the outer side wall of the hollow cylindrical specimen and fix the hollow cylindrical specimen.

[0031] In some possible implementations, each of the external fasteners 4 further includes: an upper driving rod 42, one end of which is a threaded structure, one end of which passes through the first driving hole and enters the corresponding threaded hole of the pressure head, and is threadedly connected with the outer side wall of the curved panel 41 and the pressure head 1 in sequence; each of the external fasteners 4 further includes: a lower driving rod 43, one end of which is a threaded structure, one end of which passes through the second driving hole and abuts against the outer side wall of the hollow cylindrical sample, and the lower driving rod 43 is threaded with the curved panel 41 thread connection; wherein, the maximum distance between the arc panel 41 and the inner fastener 3 in the radial direction of the inner fastener 3 is less than the length of the threaded structure at one end of the lower driving rod 43; each of the pressure head threaded holes is arranged in the pressure head 1 and extends along the radial direction of the pressure head 1; the number of the external fasteners 4 is 4; the rock stress path simulation test pressure head fastening device also includes: a plurality of displacement sensors 5, the number of the plurality of displacement sensors 5 is adapted to the number of the plurality of external fasteners 4, and each of the displacement sensors 5 is arranged at the other end of a corresponding one of the lower driving rods 43.

[0032] Specifically, in the present application, the lower end surface of the curved panel is flush with the lower end surface of the inner fastener and are located in the same plane. At the same time, the first driving hole is close to the upper end surface of the curved panel, and the second driving hole is close to the lower end surface of the curved panel, so that the lower driving rod can better press the hollow cylindrical sample against the outer wall of the inner fastener to fix the hollow cylindrical sample; the upper driving rod and the lower driving rod are both threaded structures, and the threaded structure of the upper driving rod is respectively adapted to the structure of the first driving hole and the threaded hole of the pressure head, so that a rotational force must be applied to move the upper driving rod, thereby increasing the fastening effect. At the same time, the threaded structure of the lower driving rod is adapted to the structure of the second driving hole, so that a rotational force must be applied to move the lower driving rod, thereby increasing the fastening effect of the lower driving rod on the hollow cylinder; in the rock stress path simulation test of the present application, the pressure head fastening device is used to fasten the hollow cylinder When the cylindrical sample is tightened, there is a maximum distance between the arc panel and the inner fastening space, and the distance is known to be M. This distance position can be considered as the initial position of the lower driving rod, and then the lower driving rod is screwed to the outer wall of the hollow cylindrical sample to fix the hollow cylindrical sample. A displacement sensor is provided at the other end of the lower driving rod. During this process, the displacement sensor records the distance N of the lower driving rod being screwed in, and the thickness of the hollow cylindrical sample is MN, that is, the thickness of the sample can be monitored during the process of fixing the hollow cylindrical sample, so as to achieve more efficient monitoring data. At the same time, since there is a maximum distance between the arc panel and the inner fastening space, the rock stress path simulation test head fastening device of the present application is suitable for rock stress path simulation tests of different outer diameters within the maximum distance, and has a simple structure and strong detachability.

[0033] In some possible implementations, the rock stress path simulation test pressure head fastening device also includes: four anti-slip washers, the first anti-slip washer passes through the inner fastener and is arranged on the lower end surface of the pressure head, the second anti-slip washer is arranged on the inner side of the arc panel in close contact with the arc panel; the third anti-slip washer is arranged on one end of the lower driving rod, and the fourth anti-slip washer is arranged on the outer side wall of the inner fastener.

[0034] Specifically, by arranging an anti-skid washer, the friction between the pressure head fastening device and the hollow cylindrical sample is increased, thereby enhancing the integrity of the fastening device and the rock sample, and ensuring the smooth progress of the torsion shear test; when the inner diameter of the hollow cylindrical sample is larger than the outer diameter of the inner fastener, the thickness of the fourth anti-skid washer can be increased accordingly, so that the outer wall of the inner fastener is tightly attached to the inner wall of the hollow cylindrical sample through the fourth anti-skid washer, thereby enhancing the integrity of the fastening device and the rock sample, and ensuring the smooth progress of the torsion shear test.

[0035] The preferred specific embodiments of the present invention are described in detail above. It should be understood that a person skilled in the art can make many modifications and changes based on the concept of the present invention without creative work. Therefore, any technical solution that can be obtained by a person skilled in the art through logical analysis, reasoning or limited experiments based on the concept of the present invention on the basis of the prior art should be within the scope of protection determined by the claims.

Claims

1. A rock stress path simulation test head fastening device, characterized in that: The rock stress path simulation test pressure head fastening device comprises: A pressure head (1), wherein a square groove (2) is provided at the center of the upper end surface of the pressure head (1); An internal fastener (3), the internal fastener (3) being located below the pressing head (1), and one end of the internal fastener (3) being fixedly connected to the lower end surface of the pressing head (1); A plurality of external fasteners (4), wherein the plurality of external fasteners (4) are evenly arranged on the periphery of the pressing head (1), and the plurality of external fasteners (4) are detachably connected to the outer side wall of the pressing head (1); The pressure head (1) is of cylindrical structure, the inner fastener (3) is of cylindrical structure, the central axis of the inner fastener (3) and the pressure head (1) are located on the same straight line, and the other end of the inner fastener (3) enters into one end of the hollow cylindrical sample and contacts the inner wall of the hollow cylindrical sample.

2. A rock stress path simulation test pressure head fastening device as claimed in claim 1, characterized in that: Each of the outer fasteners (4) comprises: A curved panel (41), wherein the center of the curved panel (41) is located on the central axis of the pressure head (1), and the central angle of the curved panel (41) is 45°; a first driving hole and a second driving hole are provided at the midline position of the curved panel (41) along the radial direction of the pressure head, and the second driving hole is located directly below the first driving hole.

3. A rock stress path simulation test pressure head fastening device as claimed in claim 2, characterized in that: The first driving hole and the second driving hole are both threaded holes.

4. A rock stress path simulation test pressure head fastening device as claimed in claim 3, characterized in that: A plurality of press head threaded holes are evenly arranged on the outer side wall of the press head (1), and a plurality of the press head threaded holes have a plurality of the first driving holes that are matched in number, and each of the press head threaded holes is matched in position with a corresponding one of the first driving holes.

5. A rock stress path simulation test pressure head fastening device as claimed in claim 4, characterized in that: Each of the outer fasteners (4) further comprises: An upper driving rod (42), one end of which is in a threaded structure, and one end of which passes through the first driving hole and enters the corresponding threaded hole of the pressing head, and is threadedly connected with the outer side wall of the curved panel (41) and the pressing head (1) in sequence.

6. A rock stress path simulation test pressure head fastening device as claimed in claim 5, characterized in that: Each of the outer fasteners (4) further comprises: A lower driving rod (43), one end of which is in a threaded structure, one end of which passes through the second driving hole and abuts against the outer wall of the hollow cylindrical sample, and the lower driving rod (43) is threadedly connected to the curved panel (41); Wherein, the maximum distance between the arc-shaped panel (41) and the inner fastener (3) in the radial direction of the inner fastener (3) is smaller than the length of the threaded structure at one end of the lower driving rod (43).

7. A rock stress path simulation test pressure head fastening device according to claim 6, characterized in that: Each of the press head threaded holes is arranged in the press head (1) and extends in the radial direction of the press head (1).

8. A rock stress path simulation test pressure head fastening device according to claim 7, characterized in that: The number of the external fasteners (4) is 4.

9. A rock stress path simulation test pressure head fastening device as claimed in claim 8, characterized in that: The rock stress path simulation test pressure head fastening device also includes: A plurality of displacement sensors (5), the number of the displacement sensors (5) being adapted to the number of the external fasteners (4), and each of the displacement sensors (5) being arranged at the other end of a corresponding lower driving rod (43).

10. A rock stress path simulation test pressure head fastening device as claimed in claim 9, characterized in that: The rock stress path simulation test pressure head fastening device also includes: Four anti-slip washers, the first anti-slip washer passes through the inner fastener and is arranged on the lower end surface of the pressure head, the second anti-slip washer is arranged on the inner side of the arc panel in close contact with the arc panel; the third anti-slip washer is arranged on one end of the lower driving rod, and the fourth anti-slip washer is arranged on the outer side wall of the inner fastener.

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