US 11,835,436 B2
Specimen preparation method for eliminating membrane penetration effect on highly-weathered rock
Xianwei Zhang, Wuhan (CN); Xinyu Liu, Wuhan (CN); Chao Ma, Wuhan (CN); Jijun Du, Wuhan (CN); Ruiduo Li, Wuhan (CN); and Cheng Chen, Wuhan (CN)
Assigned to Institute of Rock and Soil Mechanics, Chinese Academy of Sciences, Wuhan (CN)
Filed by Institute of Rock and Soil Mechanics, Chinese Academy of Sciences, Wuhan (CN)
Filed on Mar. 10, 2021, as Appl. No. 17/198,156.
Application 17/198,156 is a continuation of application No. PCT/CN2019/077577, filed on Mar. 9, 2019.
Claims priority of application No. 201811393379.1 (CN), filed on Nov. 21, 2018.
Prior Publication US 2021/0190649 A1, Jun. 24, 2021
Int. Cl. G01N 1/28 (2006.01); G01N 1/30 (2006.01); G01N 33/24 (2006.01)
CPC G01N 1/286 (2013.01) [G01N 33/24 (2013.01); G01N 2001/2873 (2013.01); G01N 2001/305 (2013.01); G01N 2203/0256 (2013.01)] 4 Claims
OG exemplary drawing
 
1. A specimen preparation method, comprising:
(1) taking a soil specimen out of a soil specimen tube or a packaging bag, removing a soil layer on a surface of the soil specimen by cutting to obtain a standard cylindrical triaxial specimen, and testing a diameter of the specimen with a slide caliper and recording the diameter as d1;
(2) laying a wet filter paper on upper and lower surfaces of the specimen, smearing a liquid latex on a peripheral surface of the specimen for packaging and leveling with a cutter to make the peripheral surface of the specimen smooth, and placing the packaged specimen in a moisture preservation vat and letting it stand until the liquid latex on the peripheral surface of the specimen is cured;
(3) disposing a membrane tube around a membrane, turning two ends of the membrane outwards to be attached to an outside of the membrane tube and the portions located outside the membrane tube of the membrane are banded with rubber bands;
inserting a pointed end of a plastic suction bulb into a suction hole of the membrane tube, and pressing the plastic suction bulb to exhaust air between the membrane and the membrane tube; and
dipping the liquid latex with a finger wearing a latex glove into the liquid latex and smearing in the membrane, wherein an average thickness of the liquid latex smeared in the membrane is 0.1 mm;
(4) placing the specimen processed in step (2) into the membrane sleeve prepared in step (3) and integrally curing with the membrane sleeve, wherein an inner surface of the membrane sleeve is coated with the liquid latex, and a thickness of the membrane sleeve is d0;
(5) instantly placing the specimen processed in step (4) in a triaxial confining pressure chamber after porous stones are placed in an upper portion and a lower portion of the specimen, respectively, applying a confining pressure to press the liquid latex into the specimen, and letting the specimen stand until the liquid latex is cured, wherein the confining pressure is 10 kPa; and
(6) releasing the confining pressure, removing the membrane sleeve, measuring an outer diameter d2 of the specimen with a slide caliper, and loading a specimen meeting d2/d1<1.01 for a triaxial shear test.