CN-121994646-A - Multi-scale experimental device and method for osmotic injection of micron biochar suspension into soil body

CN121994646ACN 121994646 ACN121994646 ACN 121994646ACN-121994646-A

Abstract

The invention discloses a multi-scale experimental device and a method for injecting micro-charcoal suspension into soil body by infiltration, belonging to the technical field of environmental engineering geology, wherein the device comprises a soil column simulation sampling system, a site injection well simulation sampling system, an injection pressure control system, a data acquisition system and a waste liquid collection system which are arranged in parallel; the injection pressure control system provides constant pressure for suspension injection, the data acquisition system acquires seepage parameters such as pore water pressure, flow and the like in real time, and the waste liquid collection system is used for collecting experimental waste liquid. The invention can synchronously develop the simulation experiment of the infiltration injection of the micro-charcoal suspension liquid with the soil column scale and the field injection well scale, realizes the uniform constant-pressure injection of the suspension liquid and the nondestructive sampling of undisturbed soil samples, provides reliable experimental support for the research of the migration-retention-balance dynamic evolution rule of the micro-charcoal suspension liquid in the soil body, and solves the technical bottleneck that the prior art lacks a special multi-scale simulation device, experimental working conditions and engineering actual disjoint.

Inventors

GUO YULIANG
SANG SHUXUN
CAO LIWEN
ZHANG RUI
Tan Laolin
LI JIADAI
TENG HONGBO

Assignees

中国矿业大学

Dates

Publication Date: 20260508
Application Date: 20260326

Claims (10)

1. The multi-scale experimental device for infiltration injection of the micro biochar suspension into the soil body comprises an injection pressure control system, a data acquisition system and a waste liquid collection system, and is characterized by further comprising a soil column simulation sampling system and a site injection well simulation sampling system; the injection pressure control system is respectively communicated with the earth column simulation sampling system and the site injection well simulation sampling system through liquid pipelines and is used for providing constant air pressure and stable injection pressure for injection of the micron biochar suspension; the data acquisition system is electrically connected with the earth column simulation sampling system and the site injection well simulation sampling system through a data transmission line respectively and is used for acquiring and recording seepage parameters in the experimental process; the waste liquid collecting system is respectively communicated with the earth pillar simulation sampling system and the site injection well simulation sampling system through liquid pipelines and is used for collecting waste liquid flowing out in the experimental process; The earth pillar simulation sampling system and the site injection well simulation sampling system are arranged in parallel and used for synchronously carrying out earth pillar scale and site injection well scale simulation experiments of micro-charcoal suspension infiltration injection soil body.
2. The multi-scale experimental device according to claim 1, wherein the earth column simulation sampling system comprises a sealing cover, an effluent liquid collector, a pore water pressure sensor, a soil sample barrel, an injection liquid dispenser and a first flow sensor, wherein the soil sample barrel is a vertical columnar sealing cavity, the injection liquid dispenser is arranged at the lower end of the interior of the soil sample barrel, the effluent liquid collector is arranged at the upper end of the interior of the soil sample barrel, the sealing cover is detachably and hermetically arranged at the top of the soil sample barrel, the pore water pressure sensor is at least 3 groups and is distributed at equal intervals along the axial direction of the soil sample barrel and used for detecting pore water pressures of different depths of soil samples, the liquid inlet end of the injection liquid dispenser is communicated with the injection pressure control system through a liquid pipeline through a first injection hole valve and a first flow sensor, and the liquid outlet end of the effluent liquid collector is communicated with the waste liquid collection system through a liquid pipeline through a first outflow hole valve.
3. The multi-scale experimental device according to claim 2, wherein the injection liquid disperser is of a flat cavity structure, an injection hole is arranged in the middle of the side surface of the injection liquid disperser as a liquid inlet end, and a plurality of dispersing holes are uniformly distributed on the upper plane of the injection liquid disperser for injecting the liquid entering through the injection hole into the soil sample barrel in a splitting manner.
4. The multi-scale experimental device according to claim 2, wherein the effluent collector has a flat cavity structure, the middle part of the side surface of the effluent collector is provided with an outflow hole as an effluent end, a plurality of collecting holes are uniformly distributed on the lower plane of the effluent collector, and liquid in the soil sample barrel flows out through the collecting holes and is collected to the outflow hole to be discharged.
5. The multi-scale experimental device according to claim 1, wherein the site injection well simulation sampling system comprises an outer sleeve, an inner sleeve, a second injection hole valve, a second outflow hole valve and a second flow sensor, the outer sleeve is a sealed cavity, the inner sleeve is coaxially and detachably arranged in the outer sleeve and is used for containing experimental soil samples, the inner sleeve comprises an inner pipe and an outer pipe which are coaxially nested, a plurality of injection dispersing holes are uniformly distributed on the pipe wall of the inner pipe, a plurality of outflow collecting holes are uniformly distributed on the pipe wall of the outer pipe, the liquid inlet end of the inner pipe is communicated with an injection pressure control system through a liquid pipeline through the second injection hole valve and the second flow sensor, and the annular liquid outlet end between the outer pipe and the outer sleeve is communicated with a waste liquid collecting system through a liquid pipeline through the second outflow hole valve.
6. The multi-scale experimental device according to claim 1, wherein the injection pressure control system comprises a gas cylinder, a pressure reducing valve, a gas pressure controller, a gas pipeline, a first suspension container and a second suspension container, wherein the gas outlet end of the gas cylinder is communicated with the gas pipeline through the pressure reducing valve, the gas valve and the gas pressure controller, the gas pipeline is respectively communicated with the tops of the first suspension container and the second suspension container in a sealing manner, the liquid outlet end of the first suspension container is communicated with the earth column simulation sampling system, and the liquid outlet end of the second suspension container is communicated with the site injection well simulation sampling system.
7. The multi-scale experimental device according to claim 1, wherein the data acquisition system comprises a data acquisition device, a data transmission line and a computer, wherein the data acquisition device is respectively and electrically connected with a pore water pressure sensor, a first flow sensor and a second flow sensor of the ground injection well simulation sampling system through the data transmission line, and the data acquisition device is in communication connection with the computer through the data transmission line and is used for transmitting acquired seepage parameters to the computer for storage and analysis.
8. The multi-scale experimental device according to claim 1, wherein the waste liquid collecting system comprises a liquid pipeline and a waste liquid barrel, and the waste liquid barrel is respectively communicated with the liquid outlet ends of the earth pillar simulation sampling system and the site injection well simulation sampling system through the liquid pipeline.
9. An experimental method of a multi-scale experimental setup according to any of claims 1 to 8, comprising a column scale simulation experimental step and/or a site injection well scale simulation experimental step.
10. The method according to claim 9, wherein the earth pillar scale simulation experiment step specifically comprises: S11, preparing an experiment, namely filling a soil sample to be detected into a soil sample barrel, mounting a sealing cover, preparing a micron biochar suspension with preset concentration in a first suspension container, and completing air tightness inspection of a pipeline and a valve; S12, starting an experiment, namely opening a gas cylinder, a gas valve, a first outflow hole valve and a first injection hole valve, setting preset injection pressure through a gas pressure controller, and starting constant-pressure injection experiment; S13, stopping injection when the accumulated flow detected by the first flow sensor reaches a preset value or the permeation injection duration reaches a preset duration, and sequentially closing the first outflow hole valve and the first injection hole valve; S14, sampling in an undisturbed state, namely opening a sealing cover, opening a first injection hole valve, and completely ejecting the soil sample in the soil sample barrel by utilizing the liquid pressure of an injection end to obtain an undisturbed experimental soil sample; S15, closing a gas valve and a gas cylinder, evacuating residual liquid in a pipeline, and cleaning an experimental device; the site injection well scale simulation experiment specifically comprises the following steps: s21, preparing an experiment, namely filling a soil sample to be detected into an annulus between an inner tube and an outer tube of an inner sleeve, sealing the inner sleeve in the outer sleeve, preparing a micron biochar suspension with preset concentration in a second suspension container, and completing air tightness inspection of a pipeline and a valve; S22, starting an experiment, namely opening a gas cylinder, a gas valve, a second injection hole valve and a second outflow hole valve, setting preset injection pressure through a gas pressure controller, and starting a constant pressure injection experiment; S23, stopping injection when the accumulated flow detected by the second flow sensor reaches a preset value or the permeation injection duration reaches a preset duration, and sequentially closing the second injection hole valve, the second outflow hole valve, the gas valve and the gas cylinder; s24, sampling in an undisturbed state, namely opening the outer sleeve, taking out the inner sleeve, and taking out soil from the inner sleeve radially by adopting a soil taking ring cutter to obtain undisturbed experimental soil samples with different radial distances; S25, ending the experiment, namely evacuating residual liquid in the pipeline and cleaning the experimental device.

Description

Multi-scale experimental device and method for osmotic injection of micron biochar suspension into soil body Technical Field The invention belongs to the technical field of environmental engineering geology, and particularly relates to a multi-scale simulation experiment device and method for osmotic injection of a micron biochar suspension into a soil body. Background The biochar has the core characteristics of high carbon stability, excellent pore structure development, excellent adsorption performance, alkalinity, rich oxygen-containing functional groups and the like, and has remarkable application potential in the fields of polluted soil treatment, soil reinforcement and soil carbon fixation and emission reduction. The biochar is added into the soil body, alkaline substances can be promoted to be generated by adjusting the pH value of the soil body, organic pollutants are adsorbed and fixed, degradation and conversion of the organic pollutants are restrained, agglomeration of soil particles is promoted to improve the mechanical strength of the soil body, and meanwhile, the high carbon stability of the biochar is utilized, and long-term carbon sequestration and carbon sequestration can be realized after the biochar is buried into the soil body. In engineering practice and related research of treating soil by using biochar, at present, a mixing method is routinely adopted for construction, and the method can only realize shallow soil treatment, has limited treatment depth and is difficult to meet the treatment requirement of soil sites with large burial depths. Breaks through the technical bottleneck that the injection difficulty of the biochar suspension in the soil body is large and the injection is uneven, and is a necessary premise for realizing the large-scale popularization and application of the biochar in the soil body treatment field. The micro biochar with better migration capability is adopted, and enters deep soil pores in a suspension permeation injection mode, so that the micro biochar becomes a potential technical direction for solving the deep soil treatment problem. However, at present, no special instrument and equipment specially used for researching the migration-retention-balance dynamic evolution process of the micro-charcoal suspension osmotic injection soil body exists in the industry, the conventional earth column seepage device can only carry out a single-scale experiment, the actual working condition of a site injection well cannot be restored, uniform injection of the suspension, constant-pressure working condition simulation and undisturbed soil sample nondestructive sampling are difficult to realize, and large deviation exists between laboratory research results and engineering practice, so that site construction cannot be effectively guided. Therefore, development of a multi-scale experimental device and method for injecting a special micro-biological carbon suspension into soil body in a penetrating way is needed. Disclosure of Invention Aiming at the problems existing in the prior art, the invention provides a multi-scale experimental device and a multi-scale experimental method for infiltration injection of a micro-biological carbon suspension into a soil body, which can synchronously develop simulation experiments of soil column scale and site injection well scale, realize uniform constant-pressure injection of the micro-biological carbon suspension, real-time monitoring of seepage parameters and nondestructive sampling of undisturbed soil samples, provide reliable experimental conditions for migration-retention-balance dynamic evolution law and mechanism research of infiltration injection of the micro-biological carbon suspension into the soil body, and solve the technical bottlenecks that a special experimental device is lacked in the prior art, and multi-scale synchronous simulation cannot be realized, and actual disjointing of experimental working conditions and engineering is not realized. In order to achieve the aim, the technical scheme adopted by the invention is that the multi-scale experimental device for osmotic injection of the micron biochar suspension into the soil body comprises an injection pressure control system, a data acquisition system, a waste liquid collection system, a soil column simulation sampling system and a site injection well simulation sampling system. The injection pressure control system is respectively communicated with the earth column simulation sampling system and the site injection well simulation sampling system through liquid pipelines and is used for providing constant air pressure and stable injection pressure for injection of the micron biochar suspension. The data acquisition system is electrically connected with the earth column simulation sampling system and the site injection well simulation sampling system through data transmission lines respectively and is used for acquiring and recording seepage parameters in the experim