CN210037798U - A test device for confining expansion force during hydration of expansive rock - Google Patents

Abstract

The utility model discloses a test device for limiting the expansion force in the hydration process of the expansive rock. The test device of the utility model has the advantages of simple structure, convenient operation, high accuracy and low cost. The relationship between the volume change and time and humidity during the hydration process of the expansive rock is tested, so as to provide a reference for the study of the hazard characteristics of the expansive rock. Within the range of a, this will not only save electricity but also meet the humidity requirements. The utility model can conveniently test the confining expansion force in the hydration process, and has high accuracy and low cost. It can be used to study the expansion force of expansive rock, and the bottom plate often occurs in mine tunnels, railway tunnels and cavern projects. The prevention and solution of the phenomenon of uplift, side wall extrusion and concrete lining damage have guiding significance.

Description

A test device for confining expansion force during hydration of expansive rock

technical field

The utility model relates to the technical field of expansion volume testing in the hydration process of expansive rock, in particular to a test device for confining expansion force in the process of expansive rock hydration.

Background technique

Expansive rock refers to the rock that increases in volume due to the action of water. Because it contains a large amount of hydrophilic minerals, it has a large volume change when the humidity changes, so it is called expansive rock. In recent years, in the development of resources and energy, as well as in transportation, water conservancy, electric power and urban construction projects, engineering problems caused by expansive rocks have been encountered. The bottom plate is often uplifted, the side wall is extruded, and the concrete lining is damaged, which brings serious losses to the tunnel construction. Therefore, it is of great theoretical value and engineering significance to study the volume expansion characteristics of expansive rock and understand its many hazards to tunnel engineering.

SUMMARY OF THE INVENTION

In order to better study the confining expansion characteristics of expansive rock, the utility model provides a test device for confining expansive force in the hydration process of expansive rock, which is simple in structure, convenient in operation, high in accuracy and low in cost.

In order to achieve the above-mentioned purpose, the technical scheme adopted by the present utility model is, a test device for confining expansion force in the hydration process of expansive rock, including a reaction force frame, a sealing device, a humidity sensor, a steam generator and a control device, and a reaction force frame. It includes a base and a beam, a vertical column is fixed on both sides of the upper end of the base, and the two ends of the beam are respectively fixed on the upper ends of the two vertical columns; the middle of the beam of the reaction frame is provided with a threaded through hole, and the threaded through hole is connected with internal threads There is a threaded rod, the upper end of the threaded rod is fixedly connected with a handle, the lower end of the threaded rod is fixedly connected with a mounting block, the mounting block is located in the mounting frame and is rotatably connected with the mounting frame, and the two ends of the mounting frame are respectively sleeved on two vertical columns Above, a pressure sensor is installed under the mounting frame; the sealing device includes a cylindrical sealing cover, a limited steel cylinder, an upper plate, a lower plate, an upper sealing disc and a lower sealing disc, and the top of the cylindrical sealing cover is arranged inward There is a circular upper boss, the bottom end of the cylindrical sealing cover is provided with a circular lower boss, the lower plate is placed on the base, the cylindrical sealing cover is placed on the lower plate, and the lower sealing disc is placed on the lower plate And it is located in the annular lower boss, the side limiting steel cylinder is placed between the annular upper boss and the annular lower boss, and the side limiting steel cylinder, the annular upper boss, and the annular lower boss are An annular cavity is formed between the table and the side wall of the cylindrical sealing cover; the expansive rock sample is placed in the confinement steel cylinder, and the upper sealing disk is placed on the expansive rock sample and is located in the annular upper boss; The upper plate is placed above the cylindrical sealing cover, and the upper indenter, the first spacer, the gasket and the second spacer are sequentially placed above the upper plate from bottom to top, and a displacement sensor is installed on the gasket; the probe of the humidity sensor Located in the annular cavity, the humidity sensor is connected with the control device, the control device controls the switch connected to the steam generator, and the steam generator is connected with the annular cavity through the steam pipeline; the side walls of the limited steel cylinder are evenly distributed with ventilation hole.

Preferably, the control device includes a Schmitt trigger, a NOT gate and a fixed-value resistor, the input end of the Schmitt trigger is connected to the humidity sensor, and the output end of the Schmitt trigger is connected to the steam generator via the NOT gate. The switches are connected to each other, and the switches of the Schmitt trigger, the NOT gate and the steam generator are all connected to the DC power supply through a fixed-value resistor, and the switch of the steam generator adopts an electromagnetic relay.

Preferably, the inner diameter of the annular lower boss is the same as the diameter of the lower sealing disc; the inner diameter of the annular upper boss is the same as the diameter of the upper sealing disc.

The method of using the test device for confining the expansion force in the hydration process of the expansive rock for testing, comprises the following steps in turn:

(1) After heating and dehydrating the expansive rock, use a fixture to process it into a cylindrical expansive rock sample, and put the expansive rock sample into the confining steel cylinder;

(2) Rotate the handle, the handle drives the threaded rod to move downward, and drives the mounting frame and the pressure sensor to move downward through the mounting block. When the pressure sensor touches the second pad, record the readings of the pressure sensor and displacement sensor at this time. ;

(3) The switch of the steam generator is opened by a low level trigger and closed by a high level trigger, and the steam generator is controlled to open by the control device. When the humidity sensor detects that the humidity in the sealing cover exceeds the set value a, the The Mitt trigger outputs a high level, which becomes a low level after passing through the NOT gate, the switch of the steam generator is turned off, and the steam generator stops running; when the humidity sensor detects that the humidity of the expansive rock sample is between b and a When (b<a), the Schmitt trigger continues to output a high level to keep the state of the steam generator unchanged, and the steam content in the sealing cover continues to decrease; when the humidity sensor detects that the humidity of the expansive rock sample is low At the set value b, the Schmitt trigger outputs a low level, and after passing through the NOT gate, it becomes a high level, the switch of the steam generator is turned on, and the steam generator starts to run again, so that the humidity in the sealing cover is kept at b. to within the range of a;

(4) The steam enters the sealing cover through the steam pipeline, and the expansive rock sample expands when it encounters water, and squeezes the upper plate upward, so that the indication of the displacement sensor changes; when the change of the indication of the displacement sensor exceeds the set threshold value, Rotate the handle on the reaction force frame to restore the display of the displacement sensor to the initial position, and record the data recorded by the pressure sensor and humidity sensor at this time;

(5) Repeat the above steps to obtain the expansion characteristics of the expansive rock that change with time.

The beneficial effects of the utility model are as follows: the utility model has the advantages of simple structure, convenient operation, high accuracy and low cost, and the volume change in the hydration process of the expansive rock and the relationship between time and humidity are tested by injecting water vapor into the sealing cover. In order to provide a reference for the study of the hazard characteristics of expansive rock, the switch of the steam generator is controlled by the control device, so that the humidity in the sealing cover is kept within the range of b to a, which not only saves electricity but also achieves humidity. Require. The utility model can conveniently test the confining expansion force in the hydration process, and has high precision and low cost. The prevention and solution of the phenomenon of uplift, side wall extrusion and concrete lining damage have guiding significance.

Description of drawings

Fig. 1 is the structural representation of the test device of the utility model;

Fig. 2 is the circuit schematic diagram of the control device of the utility model;

Figure 3 is a schematic side view of the side limit steel cylinder;

Figure 4 is an axial view of a C-jig for processing expansive rock samples.

Detailed ways

The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some of the embodiments of the present utility model, but not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without creative work fall within the protection scope of the present invention.

Example 1

As shown in Figures 1-3, a test device for limiting expansion force during hydration of expansive rock includes a reaction force frame, a sealing device, a humidity sensor 5, a steam generator 3 and a control device 4. The reaction force frame includes a base 27 And the beam 21, a vertical column 18 is fixed on both sides of the upper end of the base 27, and the two ends of the beam 21 are respectively fixed on the upper ends of the two vertical columns 18; A threaded rod 30 is threadedly connected in the hole, the upper end of the threaded rod 30 is fixedly connected with the handle 1, the lower end of the threaded rod 30 is fixedly connected with a mounting block 23, and the mounting block 23 is clamped in the mounting frame 24 and is rotatably connected with the mounting frame 24 , the two ends of the mounting frame 24 are respectively sleeved on the two vertical columns 18, and the pressure sensor 6 is installed under the mounting frame 24; the sealing device includes a cylindrical sealing cover 28, a limit steel cylinder 20, and an upper plate 10 , the lower plate 17, the upper sealing disc 31 and the lower sealing disc 9, the top end of the cylindrical sealing cover 28 is provided with a circular upper boss 11 inward, and the bottom end of the cylindrical sealing cover 28 is provided with a circular lower The boss 16, the lower plate 17 is placed on the base 27, the cylindrical sealing cover 28 is placed on the lower plate 17, the lower sealing disc 9 is placed on the lower plate 17 and is located in the annular lower boss 16, and the limited steel cylinder 20 It is placed between the annular upper boss 11 and the annular lower boss 16, and limits the steel cylinder 20, the annular upper boss 11, the annular lower boss 16, and the side wall of the cylindrical sealing cover A circular cavity 29 is formed between them; the gypsum rock sample 19 is placed in the confinement steel cylinder 20, and the upper sealing disc 31 is placed on the gypsum rock sample 19 and is located in the circular upper boss 11; The plate 10 is placed above the cylindrical sealing cover 28, and the upper pressure head 8, the first spacer 25, the spacer 22 and the second spacer 26 are sequentially placed above the upper plate 10 from bottom to top. Displacement sensor 7; the probe of the humidity sensor 5 is located in the annular cavity 29, the humidity sensor 5 is connected with the control device 4, the control device 4 controls the switch 15 connected to the steam generator, the steam generator 3 is connected to the annular ring through the steam pipeline 2 The cavities 29 are communicated with each other; the side walls of the limited steel cylinder 20 are evenly distributed with ventilation holes 32 .

The control device 4 includes a Schmitt trigger 12, a NOT gate 13 and a constant value resistor 14. The input end of the Schmitt trigger 12 is connected to the humidity sensor 5, and the output end of the Schmitt trigger 12 is connected to the steam via the NOT gate 13. The switch 15 of the generator is connected to each other, and the Schmidt generator 12, the NOT gate 13 and the switch 15 of the steam generator are all connected to the DC power supply, wherein the switch 15 of the steam generator adopts an electromagnetic relay, and the NOT gate 13 is connected to the coil of the electromagnetic relay. , the switch of the electromagnetic relay controls the opening and closing of the steam generator, and the switch 15 of the steam generator is triggered by a low level to open, and is triggered to be closed by a high level.

The inner diameter of the annular lower boss, the inner diameter of the annular upper boss, the diameter of the upper sealing disc, and the diameter of the lower sealing disc are all the same.

The method of using the test device for confining the expansion force in the hydration process of the expansive rock for testing, comprises the following steps in turn:

(1) The standard gypsum rock sample of φ50mm is heated and dehydrated in a constant temperature box, and then the gypsum is processed into a gypsum rock sample of φ48.85mmH35mm with a C-type fixture on the machine tool, and the gypsum rock sample is placed in the confining steel. in the barrel;

(2) Rotate the handle, the handle drives the threaded rod to move downward, and drives the mounting frame and the pressure sensor to move downward through the mounting block. When the pressure sensor touches the second pad, record the readings of the pressure sensor and displacement sensor at this time. ;

(3) The switch of the steam generator is opened by a low level trigger and closed by a high level trigger, and the steam generator is controlled to open by the control device. When the humidity sensor detects that the humidity in the sealing cover exceeds the set value a, the The Mitt trigger outputs a high level, which becomes a low level after passing through the NOT gate, the switch of the steam generator is turned off, and the steam generator stops running; when the humidity sensor detects that the humidity of the expansive rock sample is between b and a When (b<a), the Schmitt trigger continues to output a high level to keep the state of the steam generator unchanged, and the steam content in the sealing cover continues to decrease; when the humidity sensor detects that the humidity of the expansive rock sample is low At the set value b, the Schmitt trigger outputs a low level, and after passing through the NOT gate, it becomes a high level, the switch of the steam generator is turned on, and the steam generator starts to run again, so that the humidity in the sealing cover is kept at b. to within the range of a;

(4) The steam enters the sealing cover through the steam pipeline, and the expansive rock sample expands when it encounters water, and squeezes the upper plate upward, so that the indication of the displacement sensor changes; when the change of the indication of the displacement sensor exceeds the set threshold value, Rotate the handle on the reaction force frame to restore the display of the displacement sensor to the initial position, and record the data recorded by the pressure sensor and humidity sensor at this time;

(5) Repeat the above steps to obtain the data on the relationship between the confining expansion force and time of the gypsum rock sample under certain humidity conditions (b to a). By fitting the data, the confining expansion force of the gypsum rock sample can be obtained. Plot of F versus time t.

Claims (3)

1. The testing device for the lateral limit expansive force in the hydration process of the expansive rock is characterized by comprising a reaction frame, a sealing device, a humidity sensor, a steam generator and a control device, wherein the reaction frame comprises a base and a cross beam, two vertical upright columns are respectively fixed on two sides of the upper end of the base, and two ends of the cross beam are respectively fixed on the upper ends of the two vertical upright columns; the middle part of a cross beam of the reaction frame is provided with a threaded through hole, a threaded rod is connected with the threaded through hole in a threaded manner, the upper end of the threaded rod is fixedly connected with a handle, the lower end of the threaded rod is fixedly connected with an installation block, the installation block is positioned in the installation frame and is rotationally connected with the installation frame, two ends of the installation frame are respectively sleeved on the two vertical stand columns, and a pressure sensor is arranged below the installation frame; the sealing device comprises a cylindrical sealing cover, a side limit steel cylinder, an upper plate, a lower plate, an upper sealing disc and a lower sealing disc, wherein a circular upper boss is inwards arranged at the top end of the cylindrical sealing cover; the expansive rock sample is placed in the side limiting steel cylinder, and the upper sealing disc is placed on the expansive rock sample and positioned in the circular upper boss; the upper plate is placed above the cylindrical sealing cover, an upper pressure head, a first cushion block, a gasket and a second cushion block are sequentially placed above the upper plate from bottom to top, and a displacement sensor is mounted on the gasket; a probe of the humidity sensor is positioned in the annular cavity, the humidity sensor is connected with the control device, the control device controls a switch connected with the steam generator, and the steam generator is communicated with the annular cavity through a steam pipeline; and air holes are uniformly distributed on the side wall of the side limiting steel cylinder.

2. The device for testing the lateral limit expansive force in the process of hydrating the expansive rocks as claimed in claim 1, wherein the control device comprises a Schmidt trigger, a NOT gate and a fixed value resistor, wherein the input end of the Schmidt trigger is connected with the humidity sensor, the output end of the Schmidt trigger is connected with a switch of the steam generator through the NOT gate, the Schmidt trigger, the NOT gate and the switch of the steam generator are all connected with a direct current power supply through the fixed value resistor, and the switch of the steam generator adopts an electromagnetic relay.

3. The device for testing the lateral limit expansive force in the hydration process of the expanded rock as claimed in claim 1, wherein the inner diameter of the circular lower boss is the same as the diameter of the lower sealing disc; the inner diameter of the circular upper lug boss is the same as the diameter of the upper sealing disc.

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