Cohesive soil large-scale triaxial sample consolidating apparatus and consolidating method thereof

A technology for triaxial samples and cohesive soils, which is used in measurement devices, preparation of test samples, strength characteristics, etc., can solve the problems of accelerating the consolidation and drainage of triaxial samples, difficult to ensure electrical conductivity stability, and inconvenient operation. , to shorten the consolidation time, avoid leakage and short-circuit accidents, and achieve the effect of convenient operation

Inactive Publication Date: 2015-12-16

HOHAI UNIV

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AI-Extracted Technical Summary

Problems solved by technology

[0005] Before the present invention, Chinese patent (Patent No.: ZL200910183525.2) disclosed a method of electroosmotic consolidation of gravel-mixed large triaxial test. The device placed electrode plates on both ends of the triaxial sample for electroosmosis. The distance between the electrodes is the height of the entire triaxial sample. When the size of the triaxial sample is larger, the consolidation time is still longer. In addition, the wire and the electrode plate are connected by winding, which is inconvenient to operate and difficult to ensure the...

Abstract

The invention discloses a cohesive soil large-scale triaxial sample consolidating apparatus and a consolidating method thereof. The consolidating apparatus comprises a triaxial sample, a pedestal, a top cover, a rubber gasket, an electrode, a DC power supply, a bottom water penetrating board, a top water penetrating board and a combined insulated board; periphery of the cohesive soil triaxial sample is isometrically provided with electrodes, a central axis of the triaxial sample is provided with electrodes, electrodes arranged at the periphery are connected with the bottom water penetrating board at the bottom of the triaxial sample, the bottom water penetrating board is communicated with a DC power supply '-'by the combined insulated board, the electrode arranged on the central axis is connected with the top water penetrating board, the top water penetrating board is communicated with the DC power supply '+' by the combined insulated board, and the combined insulated board is composed of an insulated board, a spring and a contact. When the apparatus is used, the triaxial sample is prepared on the pedestal, simultaneously electrodes are arranged in the triaxial sample, communication between electrodes and leads are guaranteed, a rubber membrane is bundled, a confining pressure is applied, and the DC power supply is powered on for carrying out the triaxial sample consolidation. The consolidating apparatus has the advantages of simple structure, convenient operation, reliability, safety, substantially shortened consolidating time, and reduced test time and manpower.

Application Domain

Preparing sample for investigationStrength properties

Technology Topic

Tested timeRubber membrane +5

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Examples

Experimental program(1)

Example Embodiment

[0036] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. The protection scope of the present invention is not limited by specific implementations, but is limited by the claims.

[0037] The cohesive soil large-scale triaxial sample consolidation device of the present invention includes a triaxial sample 11, a base 1, a top cover 9, an electrode 12, a DC power supply 8, a bottom permeable plate 4, a top permeable plate 6 and an insulating composite plate 3. The top cover 9, the top permeable plate 6, the triaxial sample 11, the bottom permeable plate 4, and the base 1 are arranged from top to bottom, and between the top permeable plate 6 and the top cover 9, the bottom permeable plate 4 and the base 1 Insulating composite plates 3 are arranged between them; it is characterized in that: negative electrodes 122 are arranged at equal intervals around the triaxial sample 11 of cohesive soil, positive electrodes 121 are arranged on the central axis of the triaxial sample 11, and the negative electrodes 122 arranged around The bottom permeable plate 4 at the bottom of the triaxial sample 11 is connected. The bottom permeable plate 4 is connected to the "-" pole of the DC power supply 8 through the contact 16 installed in the insulating composite plate 3. The positive electrode 121 arranged on the central axis is connected to the top permeable plate 6 Connected, the top water-permeable plate 6 is connected with the "+" pole of the DC power supply 8 through the contact 16 installed in the insulating composite plate 3; the insulating composite plate 3 includes an insulating plate 18, a contact 16 and a spring 17, and the insulating plate 18 A central hole 19 is opened in the middle, and the contact 16 and the spring 17 are installed in the central hole 19.

[0038] The contact 16 is an elastic contact, including a contact a, a contact b, and a spring 17 connected between the contact a and the contact b; when the spring 17 is in a compressed state, the elastic contact is compressed The thickness is less than the thickness of the insulating plate 18, and when the spring is in a freely stretched state, the thickness of the elastic contact is greater than the thickness of the insulating plate 18.

[0039] Several groups of rows of permeable holes are uniformly distributed on the top, bottom, and insulating plates, and the permeable holes in each group of row of permeable holes are arranged in rows along the radial direction of the corresponding plate; the permeable holes The diameter is not more than 5mm.

[0040] The top and bottom permeable plates are made of aluminum alloy, the insulating plates are made of ABS plastic, and the positive and negative electrodes are made of copper sheets.

[0041] Based on the above-mentioned large-scale triaxial specimen consolidation device for cohesive soil, the present invention provides a large-scale triaxial specimen consolidation for cohesive soil. The main technical steps are:

[0042] (1) The triaxial sample 11 has a diameter of 300mm and a height of 600mm. The soil sample required for the test is calculated according to the filling density and divided into 5 equal parts.

[0043] (2) Place the insulating composite board 3, the bottom permeable board 4 and the filter paper 5 on the base 1 in sequence. The central spring 17 and the contact 16 of the insulating composite plate 3 keep the "-" pole of the DC power source 8 in communication with the bottom permeable plate 4 and the electrode 12. The diameter of the insulating composite board 3, the top water-permeable board 6, the bottom water-permeable board 4 and the filter paper 5 is the same as that of the triaxial sample 11, all of which are 300mm. The insulating composite board 3 has a thickness of 8mm, and has a uniformly distributed small hole with a diameter of 3mm for water penetration. The central hole 19 has a diameter of 40mm, and the spring 17 and the contact 16 are embedded. The bottom water-permeable plate 4 and the top water-permeable plate 6 are evenly arranged with drainage holes with a diameter of 3 mm. Four slots 13 with a length of 20 mm, a width of 10 mm and a height of 2 mm are evenly arranged on the edge of the bottom water-permeable plate 4, and the electrodes 12 can be inserted. In the center of the base 1 there is a circular hole with a diameter of 40mm and a height of 5mm. The rubber pad 2 is embedded inside, and the metal pad 15 on the outside is connected to the DC power supply 8 through a wire 7.

[0044] (3) Insert the electrode 12 in the center of the base 1, and use the layered compaction method to make the cohesive soil triaxial sample 11. The length of the electrode 12 is 600mm, and a compaction plate with a through hole in the center is selected for the electrode 12 to pass through. The distance between the bottom of the electrode and the base 1 is 30mm. Bend one end of the electrode 12 into a right angle with a length of 20 mm, and insert it into the slot 13 around the bottom permeable plate 4 along the axis.

[0045] (4) Load the prepared triaxial sample 11 into the pressure chamber of the large triaxial instrument 10. Place the filter paper 5 on the top of the triaxial sample 11. After the electrode 12 passes through the filter paper 5, bend down 90° to make it close to the top surface of the triaxial sample 11. Place the top permeable plate 6 and the insulating composite plate 3, and finally add the top The cover 9 keeps the electrode 12 in communication with the "+" pole of the DC power source 8 by the spring 17 and the contact 16. In the center of the top cover 9 there is a circular hole with a diameter of 40 mm and a height of 5 mm. The rubber pad 2 is embedded inside, and the metal pad 15 on the outside is connected to the DC power supply 8 through a wire 7.

[0046] (5) Apply a confining pressure of 100kPa to the triaxial sample 11, and open the drain valve 14.

[0047] (6) Turn on the switch of the DC power supply 8, and the triaxial specimen 11 is consolidated. The voltage of the DC power supply 8 is 24v.

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