CN-122014216-A - On-site injectability evaluation method for fault fracture zone in rich water environment

CN122014216ACN 122014216 ACN122014216 ACN 122014216ACN-122014216-A

Abstract

The invention discloses a field injectability evaluation method for a fault fracture zone under a rich water environment, and belongs to the field of poor engineering geological treatment. The method aims to solve the problems that the indexes of the existing assessment means are dispersed, the data is lagged, and the real-time visualization is difficult. The method is technically characterized by comprising the steps of obtaining initial conductivity of underground water on site, injecting saturated brine into water injection Kong Hengsu, measuring real-time conductivity of surrounding water outlets in a plurality of circles, calculating initial injectability indexes of the water outlets based on the initial conductivity and the real-time conductivity, correcting the initial indexes according to the positions of the water outlets relative to gravity and water flow directions to obtain corrected injectability indexes, and generating an injectability space distribution thermodynamic diagram based on the corrected indexes of the water outlets at the same moment. And grouting the stone body through CT scanning, calculating the setting rate, and correcting the slurry matching performance of the injectability index. The grouting reinforcement construction method is mainly used for grouting reinforcement construction guidance under rich water environments such as tunnels, underground pipelines and the like.

Inventors

WU YUN
HUANG ZHEN
LIN JIAN
ZHANG ZHONGYUAN
XIE BAO
JIN XIN
Bu Mohua
QIAN ZIWEI

Assignees

江西理工大学

Dates

Publication Date: 20260512
Application Date: 20260212

Claims (10)

1. The method for evaluating the field injectability of the fault fracture zone in the rich water environment is characterized by comprising the following steps of: Acquiring the initial conductivity of underground water in a field fault fracture zone; injecting fluid with set concentration into water injection holes of the fault fracture zone at a constant speed, and simultaneously measuring the conductivity of a plurality of water outlet holes distributed around the water injection holes in the injection process; Calculating a preliminary injectability index of each water outlet position based on the initial conductivity and the real-time conductivity of each water outlet; correcting the preliminary injectability index according to the azimuth of each water outlet relative to the gravity direction and the underground water flow direction to obtain a corrected injectability index; And generating an injectivity spatial distribution map of the fault fracture zone based on the corrected injectivity indexes of all water outlets at the same time.
2. The method for evaluating the field injectivity of a fractured zone in a rich water environment of claim 1, wherein obtaining the initial conductivity of the groundwater comprises: Introducing groundwater introduced from the fracture zone into a measurement vessel having a fixed geometry; Measuring the resistance and temperature of groundwater in the container; The initial conductivity is determined based on the geometry of the measurement vessel, the resistance, and a temperature corrected conductivity calculation relationship.
3. The method for evaluating the field injectivity of a fractured zone in a rich water environment according to claim 2, wherein the fluid injected with a set concentration is saturated brine, and the concentration of the saturated brine is determined according to the measured temperature of the groundwater.
4. The method for evaluating the field injectivity of a fault zone under a rich water environment according to claim 1, wherein a plurality of water outlet holes distributed around the water injection holes are distributed in a concentric annular shape with a plurality of circles around the water injection holes, and the number of the water outlet holes on each circle increases with the increase of the radius of the ring.
5. The method for evaluating the on-site injectability of the fault zone in the rich water environment as set forth in claim 1, wherein the process of calculating the preliminary injectability index of each water outlet position is based on the relationship that the ratio of the real-time conductivity of each water outlet to the initial conductivity is used as the preliminary injectability index of the water outlet position.
6. The method for evaluating the field injectivity of a fractured zone in a rich water environment of claim 1, wherein correcting the preliminary injectivity index comprises: Introducing a first adjustment coefficient related to the gravity direction, wherein the first adjustment coefficient is determined according to the included angle between each water outlet hole azimuth and the gravity direction; introducing a second adjustment coefficient related to the direction of the underground water flow, wherein the second adjustment coefficient is determined according to the included angle between each water outlet hole azimuth and the direction of the underground water flow; multiplying the preliminary injectability index, the first adjustment coefficient and the second adjustment coefficient to obtain the corrected injectability index.
7. The method for evaluating the field injectivity of a fractured zone in a rich water environment of claim 1, further comprising performing a slurry matching correction on the corrected injectivity index comprising: injecting the slurry to be evaluated into the water injection hole and forming a grouting stone body; Acquiring images of different sections of the grouting stone body, and calculating the setting rate of each section; And correcting the corrected injectability index again based on the setting rate.
8. The method of evaluating the on-site injectivity of a fractured zone in a rich water environment according to claim 7, wherein the process of obtaining images of different sections of the grouting stone body is realized by CT scanning, and the process of calculating the setting rate of each section is realized by identifying the pore area in the sectional image and calculating the ratio of the pore area to the total sectional area by an image processing algorithm.
9. An electronic device comprising a processor and a memory storing computer program instructions; the processor, when executing the computer program instructions, implements the method for evaluating field injectivity of a fault zone under a rich water environment as set forth in any one of claims 1-8.
10. A computer storage medium, wherein computer program instructions are stored on the computer storage medium, and when executed by a processor, the computer program instructions implement the method for evaluating field injectivity of a fault zone under a rich water environment according to any one of claims 1-8.

Description

On-site injectability evaluation method for fault fracture zone in rich water environment Technical Field The invention belongs to the technical field of poor geological treatment of engineering, and particularly relates to a field injectability evaluation method for a fault fracture zone in a rich water environment. Background The water-rich fault fracture zone is a complex geologic body which is most likely to cause disasters such as water burst, mud burst and the like in underground engineering, has rich internal water resources, strong pore connectivity and large permeability coefficient and is often accompanied with high mud content, and the feasibility of injection operations such as grouting and the like is obviously limited. Traditional on-site exploration and evaluation means mainly rely on geophysical prospecting, drilling and advanced forecasting techniques. The physical prospecting method such as a direct current method, an induced polarization method, a seismic wave method and the like can judge the distribution and water pressure characteristics of the water-rich broken zone, the drilling can provide direct parameters such as core, porosity, water content and the like, and the advanced forecasting technology such as TSP, infrared water detection and the like can identify the fault broken zone and the water-rich state thereof in advance, so that a basis is provided for subsequent construction. The grouting effect is evaluated by adopting indexes such as grouting pressure, flow rate, slurry injection amount and the like, and checking by posterior means such as inspection holes, a pressurized water test, a P-Q curve and the like. However, these methods still have significant drawbacks in practical field applications. Firstly, evaluation indexes are often scattered, only single parameters such as grouting pressure, permeability coefficient and the like are concerned, and systematic evaluation of the whole injectability of the water-rich fault fracture zone is difficult. Secondly, geophysical prospecting and drilling results are mostly obtained before construction, and the real-time updating capability is lacked, so that the grouting scheme is difficult to dynamically adjust according to actual geological conditions. Again, the critical impact of the clay content on slurry permeability is not sufficiently quantified, and the weight setting for clay in the existing model lacks sufficient experimental support, affecting the accuracy of the assessment. In addition, existing technical means for monitoring grouting effects have significant limitations. For example, seismic methods based on surface waves, refracted waves or reflected waves have weak responses to small and thin-layer hole cracks, particularly under hard coatings, wave energy is strongly damped, and it is difficult to capture small wave velocity changes inside the grouting body, so that the detection depth is limited and the resolution is not high. Although the electromagnetic method can better distinguish the hole crack distribution of different layers, the electromagnetic method has strict requirements on site conditions such as the hole drilling spacing, the water filling condition in the hole and the like, and is difficult to realize in the application scene of large-scale rapid detection. Overall, the existing monitoring method has the disadvantages of low precision, difficult operation and the like, and is difficult to meet the urgent requirement of real-time and visual monitoring of grouting effect on site. Because of the technical gap, the test method for rapidly acquiring, comprehensively analyzing and visually presenting the injectability of the fault fracture zone on site is deficient, and practical difficulties are brought to scientific formulation and dynamic optimization of a grouting reinforcement scheme in a rich water environment. Disclosure of Invention In order to solve the technical problems, the invention provides a field injectability evaluation method for a fault fracture zone in a rich water environment, which realizes real-time monitoring and dynamic visual evaluation of the injectability of the fault fracture zone through field resistivity calibration and dynamic water injection test, so that a grouting scheme can be adjusted according to real-time data. In order to achieve the above purpose, the invention provides a method for evaluating the field injectability of a fault fracture zone in a rich water environment, which comprises the following steps: Acquiring the initial conductivity of underground water in a field fault fracture zone; injecting fluid with set concentration into water injection holes of the fault fracture zone at a constant speed, and simultaneously measuring the conductivity of a plurality of water outlet holes distributed around the water injection holes in the injection process; Calculating a preliminary injectability index of each water outlet position based on the initial conductivity and t