CN107036882A - A kind of hydrostatic pressure load test small size column rock sample sealing device and method - Google Patents

Abstract

A small-sized columnar rock sample sealing device and method for hydrostatic pressure loading test, the device includes a plunger head, a rubber film, a self-adhesive tape, a heat shrinkable sleeve, an insulating tape and a steel hoop. The steps of the small-sized columnar rock sample sealing method are as follows: paste strain gauges on the lateral surface of the rock sample, and weld the lead wire; cover the sleeve with a rubber film on the lateral surface of the plunger indenter; the outer surface; place the plunger head covered with rubber film and self-adhesive tape on the upper and lower ends of the rock sample; fit the heat shrinkable sleeve on the plunger head and the outside of the rock sample, Lead out between the shrink sleeve and the self-adhesive tape; heat the heat-shrinkable sleeve with a heat-shrink gun to shrink the heat-shrinkable sleeve until the plunger head covered with rubber film and self-adhesive tape and the rock sample are wrapped by the heat-shrinkable sleeve Sealing; the outer surface of the heat-shrinkable sleeve at the position of the plunger head is wrapped with insulating tape; the steel hoop is placed on the outer surface of the insulating tape, and then the steel hoop is tightened to complete the sealing of the rock sample.

Description

A small-sized columnar rock sample sealing device and method for hydrostatic pressure loading test

technical field

The invention belongs to the technical field of rock hydrostatic pressure loading test, in particular to a small-sized columnar rock sample sealing device and method for hydrostatic pressure loading test.

Background technique

The matrix compressibility coefficient, effective compressibility coefficient and crack porosity of the rock can be obtained through the rock hydrostatic pressure loading test, and the above parameters are key indicators to characterize the physical and mechanical properties of the rock.

Hydrostatic pressure loading refers to the situation that the loading stress values of the rock in the three-axis direction are equal. In the process of hydrostatic pressure loading, in order to obtain the strain law of the rock, two acquisition methods are mainly used. The first is through the LVDT displacement sensor. measurement, the second is to measure through strain gauges.

Due to the high requirements of the LVDT displacement sensor on the rock sample, the LVDT displacement sensor cannot usually be applied to small-sized rock samples. Even if the LVDT displacement sensor is used, it must be installed on the outside of the rock sample sealing rubber sleeve. The deformation of the sleeve will have a great impact on the test accuracy, so in terms of test accuracy, small-sized rock samples are more suitable for using strain gauges.

At present, before the rock hydrostatic pressure loading test, it is first necessary to seal the rock sample. When the strain gauges are attached to the surface of the rock sample, especially when the number of strain gauges is large (usually 4 strain gauges and 8 lead wires), due to the multiple The lead wire can only be drawn out between the surface of the rock sample and the sealing rubber sleeve, which will inevitably reduce the sealing performance of the sealing rubber sleeve to the rock sample. Under the high pressure condition of 50MPa ~ 100MPa, the hydraulic oil will enter the sealing rubber sleeve through the lead wire , so as to enter the rock sample and change the physical properties of the rock sample. At this time, the experimental data obtained will be distorted, so it will lose its practical application value.

Contents of the invention

Aiming at the problems existing in the prior art, the present invention provides a small-sized columnar rock sample sealing device and method for hydrostatic pressure loading test, which effectively overcomes the drawbacks of the traditional use of sealing rubber sleeves to seal rock samples, and effectively improves the rock quality. Such tightness.

In order to achieve the above object, the present invention adopts the following technical solutions: a small-sized columnar rock sample sealing device for hydrostatic pressure loading test, including a plunger head, a rubber film, a self-adhesive tape, a heat shrinkable sleeve, an insulating tape and a steel hoop; The number of the plunger indenters is two, and the two plunger indenters are respectively installed on the upper end and the lower end of the rock sample; the rubber film is coated on the lateral surface of the plunger indenters; the self-adhesive tape is wound and coated On the outer surface of the rubber film; the heat-shrinkable sleeve is coated on the self-adhesive tape and the lateral surface of the rock sample; the insulating tape is wrapped around the outer surface of the heat-shrinkable sleeve at the position of the plunger head; the steel hoop Set on the outer surface of the insulating tape.

A method for sealing a small-sized columnar rock sample before a hydrostatic pressure loading test, using the described small-size columnar rock sample sealing device for a hydrostatic pressure loading test, comprising the following steps:

Step 1: Paste strain gauges on the lateral surface of the rock sample and weld the leads;

Step 2: Cover the sleeve with a rubber film on the side surface of the plunger head;

Step 3: Wrap the self-adhesive tape on the outer surface of the rubber film;

Step 4: Place the plunger head covered with rubber film and self-adhesive tape on the upper and lower ends of the rock sample;

Step 5: Put the heat-shrinkable sleeve on the plunger head and the outside of the rock sample, and at the same time lead the lead wire of the strain gauge from between the heat-shrinkable sleeve and the self-adhesive tape;

Step 6: Heat the heat-shrinkable sleeve with a heat-shrinking gun to shrink the heat-shrinkable sleeve until the plunger head covered with rubber film and self-adhesive tape and the rock sample are wrapped and sealed by the heat-shrinkable sleeve;

Step 7: Wrap the outer surface of the heat shrinkable sleeve at the position of the plunger head with insulating tape;

Step 8: Put the steel hoop on the outer surface of the insulating tape, and then tighten the steel hoop to complete the sealing of the rock sample.

Before sticking the strain gauge, the outer surface of the rock sample needs to be polished, and the outer surface of the rock sample needs to be polished at a 45-degree angle in one direction with more than 2500 mesh sandpaper to ensure that the strain gauge is pasted smoothly on the rock sample surface Spend.

Before coating the rubber film of the set, it is necessary to wipe and clean the side surface of the plunger head, and the wiping cleaning agent is alcohol, and the sealing degree of the rubber film and the plunger head is improved by wiping and cleaning the side surface of the plunger head .

Beneficial effects of the present invention:

Compared with the prior art, the present invention effectively overcomes the defect of lax sealing when the sealing rubber sleeve is traditionally used to seal the rock sample, effectively improves the sealing performance of the rock sample, and makes the data obtained in the test more real and reliable.

Description of drawings

Fig. 1 is a perspective view of a small-sized columnar rock sample sealing device for a hydrostatic pressure loading test of the present invention;

Fig. 2 is a front sectional view of a small-sized columnar rock sample sealing device for a hydrostatic pressure loading test of the present invention;

Fig. 3 is an enlarged view of part I in Fig. 2;

In the figure, 1—plunger indenter, 2—rubber film, 3—self-adhesive tape, 4—heat shrink sleeve, 5—insulating tape, 6—steel hoop, 7—rock sample.

detailed description

The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

As shown in Figures 1 to 3, a small-sized columnar rock sample sealing device for hydrostatic pressure loading test, including plunger head 1, rubber film 2, self-adhesive tape 3, heat shrinkable sleeve 4, insulating tape 5 and steel hoop 6; the number of the plunger indenter 1 is two, and the two plunger indenters 1 are respectively installed on the upper end and the lower end of the rock sample 7; the rubber film 2 is coated on the lateral surface of the plunger indenter 1; The self-adhesive tape 3 is wound and coated on the outer surface of the rubber film 2; the heat-shrinkable sleeve 4 is coated on the self-adhesive tape 3 and the lateral surface of the rock sample 7; the insulating tape 5 is wound and coated on the plunger head 1 The outer surface of the heat shrinkable sleeve 4 at the location; the steel hoop 6 is set on the outer surface of the insulating tape 5 .

In this embodiment, the axial length of the rock sample 7 is 50mm, and the diameter of the rock sample 7 is 25mm; The rubber film 2 is made of high-elastic latex film with a thickness of 0.25mm to 0.3mm. The width of the rubber film 2 is 25mm; the width of the self-adhesive tape 3 is 25mm; The length of the heat shrinkable sleeve 4 is 110 mm; the width of the insulating tape 5 is 20 mm.

A method for sealing a small-sized columnar rock sample before a hydrostatic pressure loading test, using the described small-size columnar rock sample sealing device for a hydrostatic pressure loading test, comprising the following steps:

Step 1: Paste the strain gauge on the lateral surface of the rock sample 7, and weld the lead wire. In this embodiment, the lead wire is 0.25mm Kynar electronic wire. The lead wire should not be too thick, which will affect the sealing effect; before pasting the strain gauge, it is necessary to The outer surface of the rock sample 7 is polished, and the outer surface of the rock sample 7 needs to be polished at an angle of 45 degrees in one direction with more than 2500 mesh sandpaper to ensure the flatness of the strain gauge on the surface of the rock sample 7;

Step 2: Cover the rubber film 2 on the side surface of the plunger head 1; before covering the rubber film 2 of the set, it is necessary to wipe and clean the side surface of the plunger head 1, and use alcohol as the cleaning agent. Improve the sealing degree between the rubber membrane 2 and the plunger head 1 by wiping and cleaning the lateral surface of the plunger head 1;

Step 3: wrap the self-adhesive tape 3 on the outer surface of the rubber film 2, and wrap the self-adhesive tape 3 for 3 layers;

Step 4: Place the plunger head 1 coated with the rubber film 2 and the self-adhesive tape 3 on the upper and lower ends of the rock sample 7;

Step 5: Put the heat-shrinkable sleeve 4 on the outside of the plunger head 1 and the rock sample 7, and at the same time lead the lead wire of the strain gauge from between the heat-shrinkable sleeve 4 and the self-adhesive tape 3;

Step 6: Use a heat shrink gun to heat the heat shrinkable sleeve 4 to shrink the heat shrinkable sleeve 4 until the plunger head 1 covered with the rubber film 2 and the self-adhesive tape 3 and the rock sample 7 are wrapped by the heat shrinkable sleeve 4 seal;

Step 7: Wrap the outer surface of the heat-shrinkable sleeve 4 at the position of the plunger head 1 and wrap it with insulating tape 5, and wrap the insulating tape 5 in 5 layers to ensure that the steel hoop 6 can be smoothly fitted;

Step 8: Put the steel hoop 6 on the outer surface of the insulating tape 5, and then tighten the steel hoop 6 to complete the sealing of the rock sample 7; the tightening force of the steel hoop 6 should be appropriate, if the tightening force is too large, the lead wire of the strain gauge will be pinched off If the tightening force is insufficient, it may lead to the possibility of seal failure when the hydrostatic pressure is high.

The solutions in the embodiments are not intended to limit the scope of patent protection of the present invention, and all equivalent implementations or changes that do not deviate from the present invention are included in the patent scope of this case.

Claims (4)

1. a kind of hydrostatic pressure load test small size column rock sample sealing device, it is characterised in that：Including plunger pressure head, rubber Epithelium, certainly glutinous band, thermal shrinkable sleeve, insulating tape and stirrup；The plunger pressure head quantity is two, and two plunger pressure heads are respectively mounted In the top and bottom of rock sample；The rubber membrane is coated on plunger pressure head lateral surface；It is described to be coated on rubber from glutinous band winding Film outer surface；The thermal shrinkable sleeve is coated on from glutinous band and rock sample lateral surface；The insulating tape is wrapped around in plunger pressure head Thermal shrinkable sleeve outer surface at position；The stirrup is sleeved on insulating tape outer surface.

2. the small size column rock sample encapsulating method before a kind of hydrostatic pressure load test, is employed quiet described in claim 1 Water pressure load test small size column rock sample sealing device, it is characterised in that comprise the following steps：

Step one：Foil gauge, and welding lead are pasted in rock sample lateral surface；

Step 2：Rubber membrane is loaded onto in plunger pressure head lateral surface wrap；

Step 3：Rubber film outer surface will be coated on from glutinous band winding；

Step 4：Rubber membrane will be coated and the upper and lower ends of rock sample are placed into from the plunger pressure head for sticking band；

Step 5：Thermal shrinkable sleeve is sleeved on the outside of plunger pressure head and rock sample, while by the lead of foil gauge from thermal shrinkable sleeve with sticking certainly Drawn between band；

Step 6：Thermal shrinkable sleeve is heated using pyrocondensation rifle, thermal shrinkable sleeve is shunk, until having coated rubber membrane and having sticked band certainly Plunger pressure head and rock sample are by thermal shrinkable sleeve environmental sealing；

Step 7：Thermal shrinkable sleeve outer surface at plunger pressure head position is wrapped around insulating tape；

Step 8：Stirrup is sleeved on insulating tape outer surface, stirrup is then tightened, the sealing of rock sample is completed.

3. the small size column rock sample encapsulating method before a kind of hydrostatic pressure load test according to claim 2, it is special Levy and be：, it is necessary to polish the outer surface of rock sample before foil gauge is pasted, and need to use sand paper more than 2500 mesh with One direction is polished rock sample outer surface in 45 degree of angles, to ensure stickup flatness of the foil gauge on rock sample surface.

4. the small size column rock sample encapsulating method before a kind of hydrostatic pressure load test according to claim 2, it is special Levy and be：, it is necessary to carry out wiping cleaning to plunger pressure head lateral surface before cladding suit rubber membrane, and cleaning agent is selected With alcohol, the tightness of rubber membrane and plunger pressure head is improved by wiping cleaning plunger pressure head lateral surface.