A combined sample preparation device and method for microbial batch reinforcement of sandy soil

A technology of microorganisms and sand, which is applied in the preparation of test samples, etc., can solve the problems of uneven solidification degree in the axial direction of sand columns and difficulty in preparing sand columns, so as to enhance physical and mechanical properties, maintain mechanical properties, and prevent sand leakage Effect

Active Publication Date: 2021-04-16
NANJING UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0009] Aiming at the technical problem that it is difficult for the sample preparation device in the prior art to prepare a large number of uniformly reinforced standardized sand columns, and the prepared sand columns are not uniformly solidified in the axial direction, the present invention provides a sample preparation device and method

Method used

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  • A combined sample preparation device and method for microbial batch reinforcement of sandy soil
  • A combined sample preparation device and method for microbial batch reinforcement of sandy soil
  • A combined sample preparation device and method for microbial batch reinforcement of sandy soil

Examples

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Embodiment 1

[0071] Such as Figure 1~3 As shown, the sample preparation device of a kind of microbial batch reinforcement sand used in the present invention comprises a cement curing box 1, a sand filling mold combination and a sample loading tool; wherein, the cement curing box includes a interlayer water tank 4, an interlayer water tank 4 Inside is equipped with a temperature-controllable heater 2 and a circulating water pump 3; the sand-filled mold assembly placed in the cement curing box 1 includes a soft plastic tube 12, the outer wall of which is wrapped with gauze 15, the upper and lower openings of the soft plastic tube 12, and the side wall Open air holes 13 with a diameter of 5 mm, and the air hole interval is 5 mm; it also includes filter paper and permeable stones that cover the upper and lower openings of the soft plastic tube 12 in sequence.

[0072] The loading tool adopts Figure 4~7 As shown in the device, the sample loading tool is composed of a hollow semicircular tabl...

Embodiment 2

[0096] The device and steps in this embodiment are basically the same as in Embodiment 1, the difference is that an air pump is installed in the cementing curing box 1 to feed air into the bacteria liquid and the cementing liquid; every filling 1 cm uses a soft plastic with a cross-sectional diameter less than or equal to The metal rod with the inner diameter of the pipe 12 is pressed on the surface of the sand, and the metal rod is hit 10 times with a 1kg hammer at a speed of 2 times per second. The initial dry density ρ of the sand filling is 1.0g / cm 3 In step F, the cementing liquid is cooled to 10°C and then added to the curing box, and the sample is allowed to stand in it for 2 hours, and then the heating thermostat is adjusted to 30°C; in step G, repeat steps E and F twice; The stresses and corresponding strains experienced during uniaxial compression are shown in Table 2.

[0097] Table 2 Comparison of uniaxial compressive strength of calcareous sand in the South China ...

Embodiment 3

[0101] The device and steps in this embodiment are basically the same as those in Example 1, except that the diameter of the pores on the wall of the soft plastic pipe is 8mm, and the distance between the pores is 8mm; the cross-sectional diameter of each filling 1cm is less than or equal to the inner diameter of the soft plastic pipe 12 Press the metal rod on the sand surface, and hit the metal rod 10 times with a 1kg hammer at a speed of 2 times per second. The initial dry density ρ of the sand filling is 1.0g / cm 3 In step F, the cementing liquid is cooled to 10°C and then added to the curing box, and the sample is allowed to stand in it for 1 hour, and then the heating thermostat is adjusted to 30°C; in step G, repeat steps E and F twice; The stresses and corresponding strains experienced during uniaxial compression are shown in Table 3.

[0102] Table 3 Comparison of uniaxial compressive strength of calcareous sand in the South China Sea before and after reinforcement

[...

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Abstract

The invention discloses a combined sample preparation device and method for microbial batch reinforcement of sandy soil, and belongs to the field of calcareous sand foundation reinforcement. The device includes a cementing curing box, the cementing curing box is provided with an interlayer water tank, and a temperature-controllable heater and a circulating water pump are arranged inside the interlayer water tank; the sand-loading mold combination placed in the cementing curing box includes a soft plastic pipe , the outer wall of the soft plastic tube is wound with gauze, the upper and lower openings of the soft plastic tube are open, and the side walls are open with air holes; and filter paper and permeable stones are sequentially covered on the upper and lower openings of the soft plastic tube. The method of the invention utilizes the mineralization of the microbial bacteria liquid to cement the sand, and effectively reinforces the sand through a set of solidifying sample preparation devices designed. soil test pieces. The sample preparation device and method of the invention greatly improves the sample preparation efficiency and the uniformity of the cemented samples, and also significantly reduces the differences between different samples, so as to meet the requirements of test repeatability and multiple samples.

Description

technical field [0001] The invention belongs to the field of calcareous sand foundation reinforcement, and more specifically relates to a combined sample preparation device and method for microbial batch reinforcement of sandy soil. Background technique [0002] In the past ten years, microbial geotechnical technology has focused on microorganisms that have an impact on the physical and mechanical properties of rock and soil, and controlled and utilized them to solve problems in geological engineering. With the deepening of research, the intersection of geological engineering and microorganisms has become closer and closer, and has gradually become a hot topic, and great progress has been made. In microbial geotechnical technology, the most widely studied method is sand reinforcement by MICP method. MICP is a biologically induced mineralization that exists widely in nature. It utilizes certain urease-producing microorganisms, such as Bacillus sarcina pasteuri, to hydrolyze ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G01N1/28G01N1/30
CPCG01N1/28G01N1/30
Inventor 唐朝生尹黎阳谢约翰吕超刘博李昊施斌
Owner NANJING UNIV
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