CN116609395A - Method for determining depth and thickness of vertical separation wall - Google Patents

Abstract

The invention discloses a method for determining the depth and thickness of a vertical barrier wall, which includes drilling sampling detection, laying out high-density measuring lines, setting measurement parameters, data collection, data interpretation, and inversion result interpretation. The method for determining the depth and thickness of vertical barrier walls. Vertical barrier walls are mostly used in the isolation and control of polluted sites or used in conjunction with restoration technology. They can have both temporary and permanent repair functions, and are suitable for the restoration of large-scale industrial polluted sites. This article The data obtained by the invention is more reasonable and reliable, which provides an important basis for judging the construction quality of the vertical barrier wall, and ensures the effectiveness of the vertical barrier wall as a risk control technology in the field of environmental restoration, which has great application value.

Description

A Method of Determining the Depth and Thickness of Vertical Partition Wall

technical field

The invention belongs to the technical field of environmental restoration, and in particular relates to a method for determining the depth and thickness of a vertical barrier wall.

Background technique

Vertical barrier walls are a common risk control measure in the field of environmental remediation, especially in the control and restoration of contaminated sites. Vertical barrier walls are mostly used in the isolation and control of polluted sites or in combination with repair technologies, and can have both temporary and permanent repair functions. , suitable for large-scale industrial pollution site remediation.

For the geophysical exploration of bentonite anti-seepage curtains, the surface high-density electrical method is initially planned to conduct geophysical exploration on typical bentonite anti-seepage curtains at different construction time stages, and obtain the basic background resistivity of the site and the anti-seepage properties of different construction time stages. According to the resistivity response of bentonite in the seepage curtain, the diffusion range of bentonite in the anti-seepage curtain is preliminarily inferred; in the later stage, the cross-hole resistivity CT method is planned to be used, combined with the surface detection results and on-site construction conditions, to determine the borehole for the cross-hole resistivity CT method The layout position and depth are detected by the trans-hole resistivity CT method.

However, in practical applications, the thickness and depth of the vertical barrier wall cannot be accurately predicted, resulting in insufficient or seriously exceeded thickness and depth, resulting in low construction quality and poor barrier effect.

Contents of the invention

The purpose of the present invention is to provide a method for determining the depth and thickness of a vertical barrier wall, so as to solve the problems raised in the background art above.

In order to achieve the above object, the present invention provides the following technical solution: a method for determining the depth and thickness of a vertical barrier wall, comprising the following steps:

S1: Borehole sampling inspection. According to the position and depth of the barrier wall, drill holes are arranged on both sides of the barrier wall, the well pipe is lowered, and water samples are taken after well cleaning for multi-parameter testing;

S2: Lay out high-density measuring lines, configure electrode rods along the pre-laid measuring lines, configure electrodes according to the measurement method, connect the measuring lines to the measurement system, and detect grounding resistance at the same time;

S3: Measurement parameter setting, determine the electrode arrangement and electrode spacing according to the survey target and geological situation;

S4: Data collection, observation and recording of working date, meteorological information, point coordinates, current value, and voltage value data;

S5: Data interpretation, import the collected data into the computer, pre-process the abnormal data of the measurement data, convert the format of the processed measurement data, and invert the measurement data, and save the inversion results;

S6: Interpretation of inversion results. Interpret the inversion results to determine the depth and thickness of the survey target.

Preferably, in step S1, the distance between the drilled holes on both sides and the side facade of the vertical barrier wall is at least 1m, and the depth of the drilled holes is not less than the depth of the vertical barrier wall. The well pipe is made of PVC pipe, and the pipe wall is made of laser Slits or holes are drilled at a distance of about 1 cm. The multi-parameters include water sample detection temperature, pH, OPR, resistivity, and TDS.

Preferably, in any of the above schemes, in step S2, the measuring system adopts ABEM Terrameter LS 2 electrical instrument.

Preferably, in any of the above schemes, in step S3, the maximum power supply electrode distance should be 4 to 6 times the top buried depth of the survey object, and the measurement electrode distance should not be greater than the top buried depth of the survey target.

Preferably in any of the above schemes, in step S4, record the working date and meteorological information, determine and record the start and end points of the survey line and the coordinates of the control points, and describe the terrain and surface buildings near the survey line. When the slope is greater than 15°, measure the height of each electrode rod;

Adjust the measurement parameters and collect data according to the site conditions;

Different observation devices are used to complete data collection;

For each permutation of observations, the total number of bad points should not exceed 1% of the total number of measurements, and for re-measurement after unexpected interruption, there should be no less than 2 depth-layer re-measurement values;

For two-pole and three-pole observation devices, the voltage and current values are collected, and the apparent resistivity value is calculated separately during data processing; when the distance between the far electrodes is not more than 5 times, the far electrode correction is performed during data processing;

During on-site observation, record the arrangement position, and indicate the position of special environmental factors, and mark it on the sketch at the same time.

Preferably in any of the above schemes, in step S5,

(1) Data reading and inspection: use the data cable to import the field measurement data stored in the measurement host into the computer, check whether there are abnormal data points in the measurement data, and perform pre-processing;

(2) Convert data format: Convert the imported data into a format that can be recognized by the inversion software. When converting the format of the measurement data of the high-density resistivity method, the parameters of the measurement method, the number of electrodes, and the electrode distance must be set;

(3) Inversion: Set appropriate inversion parameters, invert the data, and save the inversion results. Preferably in any of the above schemes, (1) secondary data processing is performed during the inversion process, including:

① Elimination of bad points: In the process of collecting data, it is necessary to eliminate and interpolate the "sharp point" data with large magnitudes generated by instruments, human errors, external interference or poor electrode grounding. Eliminate or reduce its adverse effects on the inversion results;

②Inversion with terrain: The measurement results of the high-density resistivity method are greatly affected by the terrain, and the inversion with terrain data is required to record the position and elevation of representative points in the survey line;

(2) Data hybrid inversion: Using the data measured by different devices with the same geophysical method, the measured data can be fused together for inversion, which effectively improves the reliability of the inversion results.

Technical effects and advantages of the present invention: the method for determining the depth and thickness of the vertical barrier wall detects the upper area of the high-density measuring line on the ground surface, and calculates the resistivity profile through the potential difference between the electrodes on the surface measuring line. Perform inversion calculation to obtain the resistivity profile within the range of the survey line, so as to achieve the purpose of detecting the geological conditions within the range of the survey line, and realize the delineation of the range of the vertical barrier wall; The current and voltage data of the borehole are inverted to obtain the resistivity distribution cross-section between the two boreholes, and then the resistivity profile of the detection area is obtained through inversion calculation of the data, so as to determine the depth range of the vertical barrier wall. The data obtained by the invention is more reasonable and reliable, provides an important basis for judging the construction quality of the vertical barrier wall, ensures the effectiveness of the vertical barrier wall as a risk control technology in the field of environmental restoration, and has great application value.

Description of drawings

Fig. 1 is a schematic diagram of the layout of the surface high-density survey line of the present invention;

Fig. 2 is a schematic diagram of the arrangement of cross-hole high-density measuring lines according to the present invention.

Detailed ways

The specific embodiments of the present invention will be further described below in conjunction with the accompanying drawings. It should be noted here that the descriptions of these embodiments are used to help understand the present invention, but are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below may be combined with each other as long as they do not constitute a conflict with each other.

In describing the present invention, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", " Back", "Left", "Right", "Vertical", "Horizontal", "Top", "Bottom", "Inner", "Outer", "Clockwise", "Counterclockwise", "Axial", The orientation or positional relationship indicated by "radial", "circumferential", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying the referred device or element Must be in a particular orientation, be constructed in a particular orientation, and operate in a particular orientation, and therefore should not be construed as limiting the invention.

In addition, the terms "first" and "second" are used for descriptive purposes only, and cannot be interpreted as indicating or implying relative importance or implicitly specifying the quantity of indicated technical features. Thus, the features defined as "first" and "second" may explicitly or implicitly include at least one of these features.

The present invention provides a method for determining the depth and thickness of a vertical barrier wall as shown in Figure 1-2, comprising the following steps:

Step 1: Borehole sampling and inspection. According to the position and depth of the barrier wall, drill holes are arranged on both sides of the barrier wall, the well pipe is lowered, and water samples are taken after well cleaning for multi-parameter testing.

Step 2: lay out high-density measuring lines, configure electrode rods along the pre-layout measuring lines, and configure electrodes according to the measurement method; connect the measuring lines to the measurement system, and measure the grounding resistance at the same time.

The third step: measurement parameter setting, determine the electrode arrangement and electrode spacing according to the survey target, geological situation, etc.

The fourth step: data collection, observe and record the working date, meteorological information, point coordinates, current value, voltage value and other data.

The fifth step: data interpretation, importing the collected data into the computer, pre-processing the abnormal data of the measurement data, converting the format of the processed measurement data, inverting the measurement data, and saving the inversion results.

Step 6: Interpret the inversion results, interpret the inversion results, and determine the depth and thickness of the survey target.

The following conditions apply:

(1) There is a significant difference in resistivity between the survey target and the surrounding medium;

(2) The survey target can cause measurable anomalies on the surface;

(3) The electrical abnormality of the survey target can be distinguished from the interference background;

(4) Have the necessary grounding conditions.

In the first step:

The distance between the drilling holes on both sides and the side facade of the vertical barrier wall should be at least 1m; the drilling depth should not be less than the depth of the vertical barrier wall; 1cm; water sample testing temperature, pH, OPR (oxidation-reduction potential), resistivity, TDS (hardness) and other parameters.

In the second step:

The distance between the electrode rods and the length of the measuring line determine the depth that can be detected. The larger the distance and the longer the measuring line, the deeper the depth can be detected, but the resolution will be reduced. Therefore, it is necessary to conduct preliminary calculations for the depth of the detection target, and select the best balance point between the electrode rod spacing and the length of the measuring line; before formal measurement, check the grounding resistance and connection of each electrode, and pour water (or Salt water) or replace the original electrode rod with several electrodes in parallel to reduce the grounding resistance of the electrode; the measurement system uses ABEM Terrameter LS 2 electrical instrument.

In the third step:

(1) Arrangement of electrodes

The high-density resistivity method detection is a geometric detection, and it is necessary to determine the appropriate electrode arrangement according to the survey target and geological conditions. The high-density resistivity method is divided into a variety of measurement methods according to different electrode arrangements. Commonly used methods include Wenner device method, Schlumberger device method (Spey method for short), two-pole device method and dipole device method. The Wenner device and the Spey device are mainly used for vertical profile or sounding in areas with gentle strata, and the dipole device is mainly used for profile survey.

(2) Electrode distance

The maximum power supply electrode distance should be at least 4 to 6 times the top buried depth of the survey target, and the measurement electrode distance should not be greater than the top buried depth of the survey target. In the field measurement process, the main measurement parameters that determine the detection depth are: the pole distance L between the power supply electrodes and the pole distance a between the measurement electrodes, and are related to the measurement method. Whether the selection of the measurement parameters is correct or not is related to the quality of the measurement results.

In the fourth step:

(1) Record the working date and meteorological information, determine and record the coordinates of the start and end points and control points of the survey line, and make a proper description of the terrain and surface buildings near the survey line, where the difference in surface elevation is obvious (the terrain slope is greater than 15° When), the height measurement of each electrode rod must be carried out for the subsequent topographic correction;

(2) Adjust measurement parameters and collect data according to on-site conditions. During the measurement, the staff must pay attention to the electrification reaction between the electrodes on the screen, and adjust the measurement parameters to re-measure if necessary;

(3) Use different observation devices to complete data collection, and do not use the mutual conversion value in the same observation device to replace the observation data of another observation device;

(4) For each array of observations, the total number of dead pixels should not exceed 1% of the total number of measurements. For re-measurement after unexpected interruption, there should be no less than 2 re-measured values of depth layers;

(5) For two-pole and three-pole observation devices, the voltage and current values should be collected, and the apparent resistivity value should be calculated separately during data processing; Far electrode correction;

(6) During on-site observation, the arrangement position should be recorded, and the position of special environmental factors should be indicated, and it should be marked on the sketch at the same time.

In the fifth step:

(1) Data reading and inspection: import the field measurement data stored in the measurement host into the computer with a data cable. Check whether there are abnormal data points in the measurement data, and perform pre-processing.

(2) Data format conversion: Convert the imported data into a format that can be recognized by the inversion software. When converting the format of the measurement data of the high-density resistivity method, parameters such as the measurement method, the number of electrodes, and the electrode distance must be set.

(3) Inversion: Set appropriate inversion parameters, invert the data, and save the inversion results.

1) In order to obtain more accurate inversion results, combined with the actual measurement situation, secondary data processing can be performed during the inversion process, including:

①Bad point elimination: In the process of data collection, it is necessary to eliminate and interpolate the "sharp point" data with large magnitude and large value generated by the instrument, human error, external interference or poor electrode grounding, etc. To eliminate or reduce its adverse effects on the inversion results;

②Inversion with topography: The measurement results of the high-density resistivity method are greatly affected by the topography, and the inversion with topography data is required to record the positions and elevations of representative points in the survey line.

2) Data hybrid inversion: Using the data measured by different devices with the same geophysical method, the measured data can be fused together for inversion, which effectively improves the reliability of the inversion results.

In the sixth step:

Using the observation results of various devices combined with other geophysical and geochemical prospecting data, drilling (or exploratory well) data, and geological data, carry out mutual restraint and mutual verification comprehensive inference and interpretation on the cause of the homologous anomaly and the geometric parameters and electrical parameters of the anomaly source , to improve interpretation accuracy and reduce ambiguity.

Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present invention, those skilled in the art can make the above-mentioned The embodiments are subject to changes, modifications, substitutions and variations.

Claims (7)

1. A method for determining the depth and thickness of a vertical barrier wall, characterized in that: comprising the following steps: S1: Borehole sampling inspection. According to the position and depth of the barrier wall, drill holes are arranged on both sides of the barrier wall, the well pipe is lowered, and water samples are taken after well cleaning for multi-parameter testing; S2: Lay out high-density measuring lines, configure electrode rods along the pre-laid measuring lines, configure electrodes according to the measurement method, connect the measuring lines to the measurement system, and detect grounding resistance at the same time; S3: Measurement parameter setting, determine the electrode arrangement and electrode spacing according to the survey target and geological situation; S4: Data collection, observation and recording of working date, meteorological information, point coordinates, current value, and voltage value data; S5: Data interpretation, import the collected data into the computer, pre-process the abnormal data of the measurement data, convert the format of the processed measurement data, and invert the measurement data, and save the inversion results; S6: Interpretation of inversion results. Interpret the inversion results to determine the depth and thickness of the survey target. 2. A method for determining the depth and thickness of the vertical barrier wall according to claim 1, characterized in that: in step S1, the distance between the drilled holes on both sides and the distance between the side elevations of the vertical barrier wall is at least 1m, and the drill The depth of the hole is not less than the depth of the vertical barrier wall. The well pipe is made of PVC pipe, and the pipe wall is made of laser slits or drilled holes with a distance of about 1cm. The multi-parameters include water sample detection temperature, pH, OPR, resistivity , TDS. 3. A method for determining the depth and thickness of a vertical barrier wall according to claim 1, characterized in that: in step S2, the measurement system uses an ABEM Terrameter LS 2 electrical instrument. 4. A method for determining the depth and thickness of a vertical barrier wall according to claim 1, characterized in that: in step S3, the maximum power supply electrode distance should be 4 to 6 times the buried depth of the top of the survey object , the distance between the measuring electrodes is not greater than the buried depth of the top of the survey target. 5. A method for determining the depth and thickness of a vertical barrier wall according to claim 1, characterized in that: in step S4, record the working date and meteorological information, determine and record the start and end points of the survey line and the coordinates of the control points , and describe the terrain and surface buildings near the survey line, and measure the elevation of each electrode rod when the slope of the terrain is greater than 15°; Adjust the measurement parameters and collect data according to the site conditions; Different observation devices are used to complete data collection; For each permutation of observations, the total number of bad points should not exceed 1% of the total number of measurements, and for re-measurement after unexpected interruption, there should be no less than 2 depth-layer re-measurement values; For two-pole and three-pole observation devices, the voltage and current values are collected, and the apparent resistivity value is calculated separately during data processing; when the distance between the far electrodes is not more than 5 times, the far electrode correction is performed during data processing; During on-site observation, record the arrangement position, and indicate the position of special environmental factors, and mark it on the sketch at the same time. 6. A method for determining the depth and thickness of a vertical barrier wall according to claim 1, characterized in that: in step S5, (1) Data reading and inspection: use the data cable to import the field measurement data stored in the measurement host into the computer, check whether there are abnormal data points in the measurement data, and perform pre-processing; (2) Convert data format: Convert the imported data into a format that can be recognized by the inversion software. When converting the format of the measurement data of the high-density resistivity method, the parameters of the measurement method, the number of electrodes, and the electrode distance must be set; (3) Inversion: Set appropriate inversion parameters, invert the data, and save the inversion results. 7. A method for determining the depth and thickness of a vertical barrier wall according to claim 6, characterized in that: (1) performing secondary data processing in the inversion process, including: ① Elimination of bad points: In the process of collecting data, it is necessary to eliminate and interpolate the "sharp point" data with large magnitudes generated by instruments, human errors, external interference or poor electrode grounding. Eliminate or reduce its adverse effects on the inversion results; ②Inversion with terrain: The measurement results of the high-density resistivity method are greatly affected by the terrain, and the inversion with terrain data is required to record the position and elevation of representative points in the survey line; (2) Data hybrid inversion: Using the data measured by different devices with the same geophysical method, the measured data can be fused together for inversion, which effectively improves the reliability of the inversion results.