CN113820466B - Post-remediation polluted site assessment method based on engineering safety assessment - Google Patents

Abstract

The invention discloses a method for evaluating contaminated sites after remediation based on engineering safety evaluation. The corrosiveness detection index of soil samples and the corrosiveness detection index of groundwater samples are detected; S3. Calculate the hazard quotient of the construction project according to the physical and mechanical indicators of the foundation soil, including the corrosiveness detection index of the soil sample and the corrosiveness detection index of the groundwater sample, Combined with the use planning of the polluted site, the safety level of the project is divided, and the safety evaluation standard of the contaminated site is determined according to the data index corresponding to the safety level of the project; S4, the engineering safety of the restored contaminated site is judged according to the safety evaluation standard; the present invention has a reasonable design, For engineering safety evaluation with high accuracy, it is suitable for popularization and use.

Description

An assessment method for contaminated sites after remediation based on engineering safety assessment

technical field

The invention relates to the technical field of engineering safety assessment, in particular to a method for assessing contaminated sites after restoration based on engineering safety assessment.

Background technique

At present, environmental problems are the main obstacles to the reuse of contaminated sites. If the contaminated sites are reused blindly, it will cause harm to the ecological environment and human health. Therefore, a reasonable evaluation method for land reuse of contaminated sites is particularly important in the process of reuse of contaminated sites.

In the process of reusing contaminated sites, the evaluation method for remediation of contaminated sites is currently the most commonly used evaluation method for land reuse in contaminated sites. The evaluation of contaminated site remediation mainly relies on chemical analysis, that is, by measuring the content of pollutants such as toxic and harmful substances in the land of the contaminated site, for example, by determining the type of the contaminated site, and selecting the pollutants of concern for this type of contaminated site. The pollutant content is compared with the pollutant content corresponding to the preset classification threshold of each usable land. If the classification threshold of which level of usable land is satisfied, it is determined that the contaminated site can be used at this level, so as to pass The content of specific pollutants in the polluted site is determined for comparison and judgment, so as to determine whether the land of the polluted site can be reused and which level it belongs to.

However, the prior art methods for evaluating the reuse of contaminated sites have certain limitations and contingency in the process of use. Therefore, to provide a high-accuracy, widely popularized and widely used post-remediation pollution assessment method based on engineering safety assessment. Site assessment methods are imperative.

SUMMARY OF THE INVENTION

In view of the above existing technical problems, the present invention provides a safe and accurate method for evaluating contaminated sites after restoration based on engineering safety evaluation.

The technical scheme of the present invention is: a method for evaluating contaminated sites after restoration based on engineering safety evaluation, comprising the following steps:

S1. Sample collection;

S11. Carry out grid sampling distribution in the contaminated site after restoration, control the grid spacing to be 20-35m, the sampling depth to be 1-6m, and the sampling volume to be 8-15g, to collect soil samples, and then put the collected soil samples in the Air-dry under ventilated conditions, and then pass through a 50-80 mesh screen for sieving and impurity removal, and reserve;

S12. Detect the depth of the groundwater level of the contaminated site after restoration, and then establish 15-30 groundwater detection wells with a spacing of 12-45m in the contaminated site, perform well cleaning operations on each groundwater detection well, and finally collect groundwater samples;

S2, sample detection;

S21. Detect the physical and mechanical indexes of the foundation soil and the corrosiveness detection indexes of the soil samples obtained in step S11 respectively; the physical and mechanical indexes of the foundation soil of the soil samples include: characteristic value of foundation bearing capacity, moisture content, specific gravity, compressibility, compression Modulus, internal friction angle, cohesion; the corrosiveness detection indicators of soil samples include: pH, Ca ²⁺ , Mg ²⁺ , Cl ^- , SO ₄ ^2- , HCO ₃ ^- , CO ₃ ^2- soluble salt, oxidation reduction potential, polarization current density, resistivity and mass loss;

S22. Detect the corrosiveness detection indexes of each groundwater sample obtained in step S12, respectively. The corrosiveness detection indexes of the groundwater samples include: pH, Ca ²⁺ , Mg ²⁺ , Cl ^- , SO ₄ ^2- , HCO ₃ ^- , CO ₃ ^{2 -} , aggressive CO ₂ , free CO ₂ , NH ₄ ⁺ , OH ^- , total salinity;

S3. Establish an evaluation model;

S31. According to the physical and mechanical indexes of the foundation soil of the soil sample in step S21, including the corrosiveness detection index of the soil sample and the corrosiveness detection index of the groundwater sample in step S22, calculate the damage to the construction project caused by the contaminated site after restoration Quotient value, and carry out risk characterization;

S32. In combination with the use planning of the polluted site, divide the safety level of the project into 4 levels, namely, Level I, Level II, Level III and Level IV; Including corrosion rate of concrete structure and corrosion rate of steel structure; among them, the corrosion rate of concrete structure corresponding to Grade I engineering safety is 12-15g/dm ² .a, and the corrosion rate of steel structure is 8-10g/dm ² .a; Grade II engineering The corrosion rate of concrete structure corresponding to safety is 9-12g/dm ² .a, and the corrosion rate of steel structure is 6-8g/dm ² .a; the corrosion rate of concrete structure corresponding to grade III engineering safety is 6-9g/dm ² .a , the corrosion rate of steel structure is 4-6g/dm ² .a; the corrosion rate of concrete structure corresponding to grade IV engineering safety is 3-6g/dm ² .a, and the corrosion rate of steel structure is 2-4g/dm ² .a;

S4, result output;

Calculate the corrosion rate of the concrete structure and steel structure of the contaminated site after the restoration, and then judge whether the pollution risk of each sampling point of the contaminated site after the restoration can be accepted according to the safety evaluation standard in step S32; if the pollution risk is acceptable, the evaluation is over; If the risk is unacceptable, a corresponding contaminated site remediation plan shall be formulated.

Further, in step S12, during the well cleaning process of the groundwater detection well, the amount of cleaning water is 4-8 times the volume of the groundwater detection well. The representativeness of water samples in groundwater testing wells is improved.

Further, in step S12, the groundwater sample is collected after the water body in the groundwater detection well is stable for 5-12 hours; at the same time, during the groundwater sample collection process, the sampling depth is 0.4-0.7m greater than the groundwater level depth of the contaminated site after restoration, and the above operations can improve Representative groundwater samples.

Further, after the completion of step S2, descriptive statistical analysis of the data is performed on the physical and mechanical indexes of the foundation soil of the soil samples, the corrosiveness detection indexes of the soil samples, and the corrosiveness detection indexes of the groundwater samples, and the skewness, kurtosis and coefficient of variation are calculated by the data. Perform normal distribution judgment for the main measurement indicators; the above operations can improve the accuracy and reliability of the sampled data.

Further, before step S11 is performed, first determine the geotechnical distribution of the contaminated site after restoration, and after step S11 is completed, classify and count the collected soil samples according to the geotechnical distribution of the contaminated site after restoration, and obtain various types of geotechnical soils. The data samples of various geotechnical layers are interpolated by the inverse distance weighting method to obtain the data of other unmeasured positions, so as to obtain the sample data of each position of the various geotechnical layers; the above operations can significantly improve the sampling of contaminated soil. As well as the detection efficiency, it can also accurately predict the distribution of pollutants after the remediation of the contaminated site, which is of great significance to the later investigation of the contaminated site.

Further, in step S21, after the physical and mechanical indexes of the foundation soil of the soil samples and the corrosiveness detection indexes of the soil samples are detected, the detected values of the sample data of the same type of rock and soil layers are added and averaged, and the obtained average value is used as the corresponding rock and soil layer. The layer corresponds to the sample detection value of the sampling point.

Further, after step S4 is completed, supplementary sampling and data detection are performed on areas with unacceptable pollution risks. Through supplementary sampling, the interference of human factors on the evaluation results can be eliminated, and the reliability of the evaluation method of the present invention can be improved.

Further, after step S2 is completed, the physical and mechanical indexes of the foundation soil of the soil samples, the corrosiveness detection indexes of the soil samples, and the corrosiveness detection indexes of the groundwater samples are sorted; The distribution law is conducive to the secondary restoration of the polluted plots that do not meet the standards.

Further, in step S21, the soil samples are detected according to the Tessier continuous extraction method procedure, and after the detection is completed, the soil samples are classified according to GB/T 19285. Construction improves reliable theoretical guidance.

Compared with the prior art, the beneficial effects of the present invention are as follows: the present invention has a reasonable design, which is beneficial to improve the reuse rate of the polluted site after restoration; at the same time, it can provide a scientific theoretical basis for the use of the polluted place after restoration, and improve the pollution site. The accuracy of the type of land reusability; the present invention adopts the grid replenishment method in the process of collecting soil samples from polluted sites, so that the present invention can obtain higher prediction accuracy of spatial distribution of site pollutants at the same sampling point, which not only can The efficiency can be significantly improved, the prediction accuracy can be significantly improved, and a more accurate pollution prediction range can be obtained; the present invention can comprehensively understand the soil condition of the remediation area by performing multi-point sampling and detection on the remediation contaminated site, and can make a comprehensive understanding of the soil conditions in the remediation contaminated area. The scope of pollutants can be assessed, and the impact of soil remediation pollution on project safety can be quantitatively assessed, thereby providing reliable technical support for project safety construction; the invention can accurately judge the risk of redevelopment and utilization of polluted sites, coordinate the implementation of construction projects, and ensure soil and groundwater safety.

Detailed ways

Embodiment 1: A method for evaluating contaminated sites after restoration based on engineering safety evaluation, comprising the following steps:

S1. Sample collection;

S11. Carry out grid sampling distribution in the contaminated site after restoration, control the grid spacing to be 20m, the sampling depth to be 1m, and the sampling volume to be 8g, to collect soil samples, and then air-dry the collected soil samples under ventilation conditions, and then Screening and impurity removal through a 50-mesh mesh sieve, ready for use;

S12. Detect the depth of the groundwater level of the contaminated site after restoration, then establish 15 groundwater detection wells with a spacing of 12m in the contaminated site, perform well washing operations on each groundwater detection well, and finally collect groundwater samples;

S2, sample detection;

S21. Detect the physical and mechanical indexes of the foundation soil and the corrosiveness detection indexes of the soil samples obtained in step S11 respectively; the physical and mechanical indexes of the foundation soil of the soil samples include: characteristic value of foundation bearing capacity, moisture content, specific gravity, compressibility, compression Modulus, internal friction angle, cohesion; the corrosiveness detection indicators of soil samples include: pH, Ca ²⁺ , Mg ²⁺ , Cl ^- , SO ₄ ^2- , HCO ₃ ^- , CO ₃ ^2- soluble salt, oxidation reduction potential, polarization current density, resistivity and mass loss;

S22. Detect the corrosiveness detection indexes of each groundwater sample obtained in step S12, respectively. The corrosiveness detection indexes of the groundwater samples include: pH, Ca ²⁺ , Mg ²⁺ , Cl ^- , SO ₄ ^2- , HCO ₃ ^- , CO ₃ ^{2 -} , aggressive CO ₂ , free CO ₂ , NH ₄ ⁺ , OH ^- , total salinity;

S3. Establish an evaluation model;

S31. According to the physical and mechanical indexes of the foundation soil of the soil sample in step S21, including the corrosiveness detection index of the soil sample and the corrosiveness detection index of the groundwater sample in step S22, calculate the damage to the construction project caused by the contaminated site after restoration Quotient value, and carry out risk characterization;

S32. In combination with the use planning of the polluted site, divide the safety level of the project into 4 levels, namely, Level I, Level II, Level III and Level IV; Including corrosion rate of concrete structure and corrosion rate of steel structure; among them, the corrosion rate of concrete structure corresponding to Grade I engineering safety is 12-15g/dm ² .a, and the corrosion rate of steel structure is 8-10g/dm ² .a; Grade II engineering The corrosion rate of concrete structure corresponding to safety is 9-12g/dm ² .a, and the corrosion rate of steel structure is 6-8g/dm ² .a; the corrosion rate of concrete structure corresponding to grade III engineering safety is 6-9g/dm ² .a , the corrosion rate of steel structure is 4-6g/dm ² .a; the corrosion rate of concrete structure corresponding to grade IV engineering safety is 3-6g/dm ² .a, and the corrosion rate of steel structure is 2-4g/dm ² .a;

S4, result output;

Calculate the corrosion rate of the concrete structure and steel structure of the contaminated site after the restoration, and then judge whether the pollution risk of each sampling point of the contaminated site after the restoration can be accepted according to the safety evaluation standard in step S32; if the pollution risk is acceptable, the evaluation is over; If the risk is unacceptable, a corresponding contaminated site remediation plan shall be formulated.

Embodiment 2: A method for evaluating contaminated sites after restoration based on engineering safety evaluation, comprising the following steps:

S1. Sample collection;

S11. Carry out grid sampling distribution in the contaminated site after restoration, control the grid spacing to be 28m, the sampling depth to be 4m, and the sampling volume to be 13g, to collect soil samples, and then air-dry the collected soil samples under ventilation conditions. Screening and impurity removal through a 60-mesh mesh sieve, ready for use;

S12. Detect the depth of the groundwater level of the contaminated site after restoration, then establish 26 groundwater detection wells with a spacing of 30m in the contaminated site, and perform well cleaning operations on each groundwater detection well, and finally collect groundwater samples; among them, the groundwater detection wells are cleaned During the process, the amount of cleaning water is 4 times the volume of the groundwater detection well. By performing multiple well cleaning operations on the groundwater detection well, the influence of external factors on the groundwater index can be eliminated, and the representativeness of the water samples in the groundwater detection well is improved. The groundwater sample is collected after the water body in the well is stable for 5 hours; at the same time, during the groundwater sample collection process, the sampling depth is 0.4m greater than the groundwater table depth of the contaminated site after restoration, and the above operations can improve the representativeness of the groundwater sample;

S2, sample detection;

S21. Detect the physical and mechanical indexes of the foundation soil and the corrosiveness detection indexes of the soil samples obtained in step S11 respectively; the physical and mechanical indexes of the foundation soil of the soil samples include: characteristic value of foundation bearing capacity, moisture content, specific gravity, compressibility, compression Modulus, internal friction angle, cohesion; the corrosiveness detection indicators of soil samples include: pH, Ca ²⁺ , Mg ²⁺ , Cl ^- , SO ₄ ^2- , HCO ₃ ^- , CO ₃ ^2- soluble salt, oxidation reduction potential, polarization current density, resistivity and mass loss;

S22. Detect the corrosiveness detection indexes of each groundwater sample obtained in step S12, respectively. The corrosiveness detection indexes of the groundwater samples include: pH, Ca ²⁺ , Mg ²⁺ , Cl ^- , SO ₄ ^2- , HCO ₃ ^- , CO ₃ ^{2 -} , aggressive CO ₂ , free CO ₂ , NH ₄ ⁺ , OH ^- , total salinity;

S3. Establish an evaluation model;

S31. According to the physical and mechanical indexes of the foundation soil of the soil sample in step S21, including the corrosiveness detection index of the soil sample and the corrosiveness detection index of the groundwater sample in step S22, calculate the damage to the construction project caused by the contaminated site after restoration Quotient value, and carry out risk characterization;

S32. In combination with the use planning of the polluted site, divide the safety level of the project into 4 levels, namely, Level I, Level II, Level III and Level IV; Including corrosion rate of concrete structure and corrosion rate of steel structure; among them, the corrosion rate of concrete structure corresponding to Grade I engineering safety is 12-15g/dm ² .a, and the corrosion rate of steel structure is 8-10g/dm ² .a; Grade II engineering The corrosion rate of concrete structure corresponding to safety is 9-12g/dm ² .a, and the corrosion rate of steel structure is 6-8g/dm ² .a; the corrosion rate of concrete structure corresponding to grade III engineering safety is 6-9g/dm ² .a , the corrosion rate of steel structure is 4-6g/dm ² .a; the corrosion rate of concrete structure corresponding to grade IV engineering safety is 3-6g/dm ² .a, and the corrosion rate of steel structure is 2-4g/dm ² .a;

S4, result output;

Calculate the corrosion rate of the concrete structure and steel structure of the contaminated site after the restoration, and then judge whether the pollution risk of each sampling point of the contaminated site after the restoration can be accepted according to the safety evaluation standard in step S32; if the pollution risk is acceptable, the evaluation is over; If the risk is unacceptable, a corresponding contaminated site remediation plan shall be formulated.

Embodiment 3: A method for evaluating contaminated sites after restoration based on engineering safety evaluation, comprising the following steps:

S1. Sample collection;

S11. Carry out grid sampling distribution on the contaminated site after restoration, control the grid spacing to be 35m, the sampling depth to be 6m, and the sampling volume to be 15g, to collect soil samples, and then air-dry the collected soil samples under ventilation conditions, and then air-dry the collected soil samples. Screening and impurity removal through 80-mesh mesh sieve, ready for use;

S12. Detect the depth of the groundwater level of the contaminated site after restoration, then establish 30 groundwater detection wells with a spacing of 45m in the contaminated site, clean each groundwater detection well, and finally collect groundwater samples;

S2, sample detection;

S21. Detect the physical and mechanical indexes of the foundation soil and the corrosiveness detection indexes of the soil samples obtained in step S11 respectively; the physical and mechanical indexes of the foundation soil of the soil samples include: characteristic value of foundation bearing capacity, moisture content, specific gravity, compressibility, compression Modulus, internal friction angle, cohesion; the corrosiveness detection indicators of soil samples include: pH, Ca ²⁺ , Mg ²⁺ , Cl ^- , SO ₄ ^2- , HCO ₃ ^- , CO ₃ ^2- soluble salt, oxidation Reduction potential, polarization current density, resistivity, and mass loss; after the physical and mechanical indexes of the foundation soil of the soil samples and the corrosiveness detection indexes of the soil samples are detected, the detected values of the sample data of the same type of rock and soil layer are added and averaged. , and the obtained mean value is taken as the sample detection value of the corresponding sampling point of the corresponding rock and soil layer;

S22. Detect the corrosiveness detection indexes of each groundwater sample obtained in step S12, respectively. The corrosiveness detection indexes of the groundwater samples include: pH, Ca ²⁺ , Mg ²⁺ , Cl ^- , SO ₄ ^2- , HCO ₃ ^- , CO ₃ ^{2 -} , erosive CO ₂ , free CO ₂ , NH ₄ ⁺ , OH ^- , total salinity; then the physical and mechanical indicators of the foundation soil of the soil samples, the corrosion detection indicators of the soil samples and the corrosion detection indicators of the groundwater samples were carried out. Descriptive statistical analysis of the data is carried out, and the skewness, kurtosis and coefficient of variation are used as the main indicators to judge the normal distribution; through the above operations, the accuracy and reliability of the sampling data can be improved; The corrosiveness detection index of the soil sample and the corrosiveness detection index of the groundwater sample are sorted; through the above operation, the distribution law of residual pollutants in the contaminated site after restoration can be obtained, which is conducive to the secondary restoration of the contaminated land that does not meet the standard;

S3. Establish an evaluation model;

S31. According to the physical and mechanical indexes of the foundation soil of the soil sample in step S21, including the corrosiveness detection index of the soil sample and the corrosiveness detection index of the groundwater sample in step S22, calculate the damage to the construction project caused by the contaminated site after restoration Quotient value, and carry out risk characterization;

S32. In combination with the use planning of the polluted site, divide the safety level of the project into 4 levels, namely, Level I, Level II, Level III and Level IV; Including corrosion rate of concrete structure and corrosion rate of steel structure; among them, the corrosion rate of concrete structure corresponding to Grade I engineering safety is 12-15g/dm ² .a, and the corrosion rate of steel structure is 8-10g/dm ² .a; Grade II engineering The corrosion rate of concrete structure corresponding to safety is 9-12g/dm ² .a, and the corrosion rate of steel structure is 6-8g/dm ² .a; the corrosion rate of concrete structure corresponding to grade III engineering safety is 6-9g/dm ² .a , the corrosion rate of steel structure is 4-6g/dm ² .a; the corrosion rate of concrete structure corresponding to grade IV engineering safety is 3-6g/dm ² .a, and the corrosion rate of steel structure is 2-4g/dm ² .a;

S4, result output;

Calculate the corrosion rate of the concrete structure and steel structure of the contaminated site after the restoration, and then judge whether the pollution risk of each sampling point of the contaminated site after the restoration can be accepted according to the safety evaluation standard in step S32; if the pollution risk is acceptable, the evaluation is over; If the risk is unacceptable, a corresponding contaminated site remediation plan shall be formulated.

Embodiment 4: A method for evaluating contaminated sites after restoration based on engineering safety evaluation, comprising the following steps:

S1. Sample collection;

S11. First determine the geotechnical distribution of the contaminated site after restoration, and then distribute grid sampling points in the contaminated site after restoration, control the grid spacing to be 20m, the sampling depth to be 1m, and the sampling volume to be 8g, to collect soil samples, and then to The collected soil samples were air-dried under ventilation conditions, and then passed through a 50-mesh mesh sieve for sieving, impurity removal, and standby. The data samples of the rock-soil layers are interpolated by the inverse distance weight method to obtain the data of other unmeasured positions, so as to obtain the sample data of each position of the rock-soil layers; the above operations can significantly improve the Contaminated soil sampling and detection efficiency, and can also accurately predict the distribution of pollutants after the remediation of contaminated sites, which is of great significance to the later investigation of contaminated sites;

S12. Detect the depth of the groundwater level of the contaminated site after restoration, then establish 15 groundwater detection wells with a spacing of 12m in the contaminated site, perform well washing operations on each groundwater detection well, and finally collect groundwater samples;

S2, sample detection;

S21. Detect the physical and mechanical indexes of the foundation soil and the corrosiveness detection indexes of the soil samples obtained in step S11 respectively; the physical and mechanical indexes of the foundation soil of the soil samples include: characteristic value of foundation bearing capacity, moisture content, specific gravity, compressibility, compression Modulus, internal friction angle, cohesion; the corrosiveness detection indicators of soil samples include: pH, Ca ²⁺ , Mg ²⁺ , Cl ^- , SO ₄ ^2- , HCO ₃ ^- , CO ₃ ^2- soluble salt, oxidation reduction potential, polarization current density, resistivity and mass loss;

S22. Detect the corrosiveness detection indexes of each groundwater sample obtained in step S12, respectively. The corrosiveness detection indexes of the groundwater samples include: pH, Ca ²⁺ , Mg ²⁺ , Cl ^- , SO ₄ ^2- , HCO ₃ ^- , CO ₃ ^{2 -} , aggressive CO ₂ , free CO ₂ , NH ₄ ⁺ , OH ^- , total salinity;

S3. Establish an evaluation model;

S31. According to the physical and mechanical indexes of the foundation soil of the soil sample in step S21, including the corrosiveness detection index of the soil sample and the corrosiveness detection index of the groundwater sample in step S22, calculate the damage to the construction project caused by the contaminated site after restoration Quotient value, and carry out risk characterization;

S32. In combination with the use planning of the polluted site, divide the safety level of the project into 4 levels, namely, Level I, Level II, Level III and Level IV; Including corrosion rate of concrete structure and corrosion rate of steel structure; among them, the corrosion rate of concrete structure corresponding to Grade I engineering safety is 12-15g/dm ² .a, and the corrosion rate of steel structure is 8-10g/dm ² .a; Grade II engineering The corrosion rate of concrete structure corresponding to safety is 9-12g/dm ² .a, and the corrosion rate of steel structure is 6-8g/dm ² .a; the corrosion rate of concrete structure corresponding to grade III engineering safety is 6-9g/dm ² .a , the corrosion rate of steel structure is 4-6g/dm ² .a; the corrosion rate of concrete structure corresponding to grade IV engineering safety is 3-6g/dm ² .a, and the corrosion rate of steel structure is 2-4g/dm ² .a;

S4, result output;

Calculate the corrosion rate of the concrete structure and steel structure of the contaminated site after the restoration, and then judge whether the pollution risk of each sampling point of the contaminated site after the restoration can be accepted according to the safety evaluation standard in step S32; if the pollution risk is acceptable, the evaluation is over; If the risk is unacceptable, a corresponding contaminated site remediation plan shall be formulated.

Embodiment 5: a method for evaluating contaminated sites after remediation based on engineering safety evaluation, comprising the following steps:

S1. Sample collection;

S11. Carry out grid sampling distribution on the contaminated site after restoration, control the grid spacing to be 35m, the sampling depth to be 6m, and the sampling volume to be 15g, to collect soil samples, and then air-dry the collected soil samples under ventilation conditions, and then air-dry the collected soil samples. Screening and impurity removal through 80-mesh mesh sieve, ready for use;

S12. Detect the depth of the groundwater level of the contaminated site after restoration, then establish 30 groundwater detection wells with a spacing of 45m in the contaminated site, clean each groundwater detection well, and finally collect groundwater samples;

S2, sample detection;

S21. Detect the physical and mechanical indexes of the foundation soil and the corrosiveness detection indexes of the soil samples obtained in step S11 respectively; the physical and mechanical indexes of the foundation soil of the soil samples include: characteristic value of foundation bearing capacity, moisture content, specific gravity, compressibility, compression Modulus, internal friction angle, cohesion; the corrosiveness detection indicators of soil samples include: pH, Ca ²⁺ , Mg ²⁺ , Cl ^- , SO ₄ ^2- , HCO ₃ ^- , CO ₃ ^2- soluble salt, oxidation reduction potential, polarization current density, resistivity and mass loss;

S22. Detect the corrosiveness detection indexes of each groundwater sample obtained in step S12, respectively. The corrosiveness detection indexes of the groundwater samples include: pH, Ca ²⁺ , Mg ²⁺ , Cl ^- , SO ₄ ^2- , HCO ₃ ^- , CO ₃ ^{2 -} , aggressive CO ₂ , free CO ₂ , NH ₄ ⁺ , OH ^- , total salinity;

S3. Establish an evaluation model;

S31. According to the physical and mechanical indexes of the foundation soil of the soil sample in step S21, including the corrosiveness detection index of the soil sample and the corrosiveness detection index of the groundwater sample in step S22, calculate the damage to the construction project caused by the contaminated site after restoration Quotient value, and carry out risk characterization;

S32. In combination with the use planning of the polluted site, divide the safety level of the project into 4 levels, namely, Level I, Level II, Level III and Level IV; Including corrosion rate of concrete structure and corrosion rate of steel structure; among them, the corrosion rate of concrete structure corresponding to Grade I engineering safety is 12-15g/dm ² .a, and the corrosion rate of steel structure is 8-10g/dm ² .a; Grade II engineering The corrosion rate of concrete structure corresponding to safety is 9-12g/dm ² .a, and the corrosion rate of steel structure is 6-8g/dm ² .a; the corrosion rate of concrete structure corresponding to grade III engineering safety is 6-9g/dm ² .a , the corrosion rate of steel structure is 4-6g/dm ² .a; the corrosion rate of concrete structure corresponding to grade IV engineering safety is 3-6g/dm ² .a, and the corrosion rate of steel structure is 2-4g/dm ² .a;

S4, result output;

Calculate the corrosion rate of the concrete structure and steel structure of the contaminated site after the restoration, and then judge whether the pollution risk of each sampling point of the contaminated site after the restoration can be accepted according to the safety evaluation standard in step S32; if the pollution risk is acceptable, the evaluation is over; If the risk is unacceptable, a corresponding pollution site restoration plan is formulated; finally, supplementary sampling and data detection are performed for the unacceptable pollution risk area. Through supplementary sampling, the interference of human factors on the evaluation results can be eliminated, and the reliability of the evaluation method of the present invention can be improved.

Embodiment 6: A method for evaluating contaminated sites after restoration based on engineering safety evaluation, comprising the following steps:

S1. Sample collection;

S11. Carry out grid sampling distribution in the contaminated site after restoration, control the grid spacing to be 30m, the sampling depth to be 5m, and the sampling volume to be 12g, to collect soil samples, and then air-dry the collected soil samples under ventilation conditions. Screening and impurity removal through a 60-mesh mesh sieve, ready for use;

S12. Detect the depth of the groundwater level of the contaminated site after restoration, then build 25 groundwater detection wells with a spacing of 30m in the contaminated site, perform well cleaning operations on each groundwater detection well, and finally collect groundwater samples;

S2, sample detection;

S21. Detect the physical and mechanical indexes of the foundation soil and the corrosiveness detection indexes of the soil samples obtained in step S11 respectively; the physical and mechanical indexes of the foundation soil of the soil samples include: characteristic value of foundation bearing capacity, moisture content, specific gravity, compressibility, compression Modulus, internal friction angle, cohesion; the corrosiveness detection indicators of soil samples include: pH, Ca ²⁺ , Mg ²⁺ , Cl ^- , SO ₄ ^2- , HCO ₃ ^- , CO ₃ ^2- soluble salt, oxidation Reduction potential, polarization current density, resistivity and mass loss; soil samples were tested according to the Tessier continuous extraction method. After the test, the soil samples were classified according to GB/T 19285. Classification can improve reliable theoretical guidance for subsequent engineering construction;

S22. Detect the corrosiveness detection indexes of each groundwater sample obtained in step S12, respectively. The corrosiveness detection indexes of the groundwater samples include: pH, Ca ²⁺ , Mg ²⁺ , Cl ^- , SO ₄ ^2- , HCO ₃ ^- , CO ₃ ^{2 -} , aggressive CO ₂ , free CO ₂ , NH ₄ ⁺ , OH ^- , total salinity;

S3. Establish an evaluation model;

S31. According to the physical and mechanical indexes of the foundation soil of the soil sample in step S21, including the corrosiveness detection index of the soil sample and the corrosiveness detection index of the groundwater sample in step S22, calculate the damage to the construction project caused by the contaminated site after restoration Quotient value, and carry out risk characterization;

S32. In combination with the use planning of the polluted site, divide the safety level of the project into 4 levels, namely, Level I, Level II, Level III and Level IV; Including corrosion rate of concrete structure and corrosion rate of steel structure; among them, the corrosion rate of concrete structure corresponding to Grade I engineering safety is 12-15g/dm ² .a, and the corrosion rate of steel structure is 8-10g/dm ² .a; Grade II engineering The corrosion rate of concrete structure corresponding to safety is 9-12g/dm ² .a, and the corrosion rate of steel structure is 6-8g/dm ² .a; the corrosion rate of concrete structure corresponding to grade III engineering safety is 6-9g/dm ² .a , the corrosion rate of steel structure is 4-6g/dm ² .a; the corrosion rate of concrete structure corresponding to grade IV engineering safety is 3-6g/dm ² .a, and the corrosion rate of steel structure is 2-4g/dm ² .a;

S4, result output;

Calculate the corrosion rate of the concrete structure and steel structure of the contaminated site after the restoration, and then judge whether the pollution risk of each sampling point of the contaminated site after the restoration can be accepted according to the safety evaluation standard in step S32; if the pollution risk is acceptable, the evaluation is over; If the risk is unacceptable, a corresponding contaminated site remediation plan shall be formulated.

Embodiment 7 A method for evaluating contaminated sites after restoration based on engineering safety assessment, comprising the following steps:

S1. Sample collection;

S11. First, determine the geotechnical distribution of the contaminated site after restoration, and arrange grid sampling points in the contaminated site after restoration. Control the grid spacing to be 35m, the sampling depth to be 6m, and the sampling volume to be 15g, to collect soil samples, and then to collect soil samples. The collected soil samples were air-dried under ventilation conditions, and then passed through an 80-mesh mesh sieve for sieving, impurity removal, and standby; finally, the collected soil samples were classified and counted according to the geotechnical distribution of the contaminated site after restoration, and various types of soil samples were obtained. Geotechnical layer data samples, using the inverse distance weighting method to interpolate data from other unmeasured locations to obtain sample data for each location of various geotechnical layers; the above operations can significantly improve pollution. Soil sampling and detection efficiency can also be used to accurately predict the distribution of pollutants after the remediation of contaminated sites, which is of great significance to the later investigation of contaminated sites;

S12. Detect the depth of the groundwater level of the contaminated site after restoration, then establish 30 groundwater detection wells with a spacing of 45m in the contaminated site, and perform well cleaning operations on each groundwater detection well, and finally collect groundwater samples; among them, the groundwater detection wells are cleaned During the process, the amount of cleaning water is 8 times the volume of the groundwater detection well. By performing multiple well cleaning operations on the groundwater detection well, the influence of external factors on the groundwater index can be eliminated, and the representativeness of the water samples in the groundwater detection well is improved; The groundwater sample was collected after the water body in the well was stable for 12 hours; at the same time, during the groundwater sample collection process, the sampling depth was 0.7m greater than the groundwater table depth of the contaminated site after restoration. The above operations can improve the representativeness of groundwater samples;

S2, sample detection;

S21. Detect the physical and mechanical indexes of the foundation soil and the corrosiveness detection indexes of the soil samples obtained in step S11 respectively; the physical and mechanical indexes of the foundation soil of the soil samples include: characteristic value of foundation bearing capacity, moisture content, specific gravity, compressibility, compression Modulus, internal friction angle, cohesion; the corrosiveness detection indicators of soil samples include: pH, Ca ²⁺ , Mg ²⁺ , Cl ^- , SO ₄ ^2- , HCO ₃ ^- , CO ₃ ^2- soluble salt, oxidation Reduction potential, polarization current density, resistivity and mass loss; soil samples were tested according to the Tessier continuous extraction method. After the test, the soil samples were classified according to GB/T 19285. The classification of grades can provide reliable theoretical guidance for subsequent engineering construction; after the physical and mechanical indicators of the foundation soil of the soil samples and the corrosiveness detection indicators of the soil samples are detected, the detection values of the sample data of the same type of rock and soil layer are added and averaged. , and the obtained mean value is taken as the sample detection value of the corresponding sampling point of the corresponding rock and soil layer;

S22. Detect the corrosiveness detection indexes of each groundwater sample obtained in step S12, respectively. The corrosiveness detection indexes of the groundwater samples include: pH, Ca ²⁺ , Mg ²⁺ , Cl ^- , SO ₄ ^2- , HCO ₃ ^- , CO ₃ ^{2 -} , erosive CO ₂ , free CO ₂ , NH ₄ ⁺ , OH ^- , total salinity; then the physical and mechanical indicators of the foundation soil of the soil samples, the corrosion detection indicators of the soil samples and the corrosion detection indicators of the groundwater samples were carried out. Descriptive statistical analysis of the data is carried out, and the skewness, kurtosis and coefficient of variation are used as the main indicators to judge the normal distribution; through the above operations, the accuracy and reliability of the sampling data can be improved; The corrosiveness detection index of the soil sample and the corrosiveness detection index of the groundwater sample are sorted; through the above operation, the distribution law of residual pollutants in the contaminated site after restoration can be obtained, which is conducive to the secondary restoration of the contaminated land that does not meet the standard;

S3. Establish an evaluation model;

S31. According to the physical and mechanical indexes of the foundation soil of the soil sample in step S21, including the corrosiveness detection index of the soil sample and the corrosiveness detection index of the groundwater sample in step S22, calculate the damage to the construction project caused by the contaminated site after restoration Quotient value, and carry out risk characterization;

S32. In combination with the use planning of the polluted site, divide the safety level of the project into 4 levels, namely, Level I, Level II, Level III and Level IV; Including corrosion rate of concrete structure and corrosion rate of steel structure; among them, the corrosion rate of concrete structure corresponding to Grade I engineering safety is 12-15g/dm ² .a, and the corrosion rate of steel structure is 8-10g/dm ² .a; Grade II engineering The corrosion rate of concrete structure corresponding to safety is 9-12g/dm ² .a, and the corrosion rate of steel structure is 6-8g/dm ² .a; the corrosion rate of concrete structure corresponding to grade III engineering safety is 6-9g/dm ² .a , the corrosion rate of steel structure is 4-6g/dm ² .a; the corrosion rate of concrete structure corresponding to grade IV engineering safety is 3-6g/dm ² .a, and the corrosion rate of steel structure is 2-4g/dm ² .a;

S4, result output;

Calculate the corrosion rate of the concrete structure and steel structure of the contaminated site after the restoration, and then judge whether the pollution risk of each sampling point of the contaminated site after the restoration can be accepted according to the safety evaluation standard in step S32; if the pollution risk is acceptable, the evaluation is over; If the risk is unacceptable, a corresponding pollution site restoration plan is formulated; finally, supplementary sampling and data detection are performed for the unacceptable pollution risk area. Through supplementary sampling, the interference of human factors on the evaluation results can be eliminated, and the reliability of the evaluation method of the present invention can be improved.

Test Example: The methods of Examples 1-7 of the present invention were used to evaluate the post-repair safety of different polluted sites in a chemical park in southern my country, and 5 years after the evaluation was completed, concrete structure samples of buildings in polluted sites of various safety levels were collected respectively. The corrosion rate was tested with steel structure samples, and the test results were compared with the standard data. The comparison deviation is shown in Table 1;

Table 1. The impact of different evaluation methods on the evaluation results;

From the data in Table 1, it can be seen that compared with Example 1, Example 2 can improve the representativeness of groundwater samples by controlling the distance between the depth of groundwater sampling and the depth of the groundwater table in the contaminated site after restoration, and controlling the stabilization time of the water body in the detection well. The accuracy of the evaluation results of the impact of groundwater samples on the corrosion rate of concrete structures; Example 3 is compared with Example 1. Descriptive statistical analysis of data and judgment of normal distribution can improve the accuracy and reliability of sampling data. Through the physical and mechanical indicators of soil samples, the corrosion detection indicators of soil samples, and the corrosion detection indicators of groundwater samples. Sorting can obtain the distribution law of residual pollutants in the contaminated site after restoration, which is beneficial to carry out secondary restoration work on the contaminated plots that do not meet the standards; Example 4 is compared with Example 1, by determining the distribution of geotechnical soils in the contaminated site after restoration It can significantly improve the sampling and detection efficiency of contaminated soil, and at the same time, it can also accurately predict the distribution of pollutants after the remediation of the contaminated site, which is of great significance for the investigation of the contaminated site in the later stage; Example 5 and Example 1 In contrast, by supplementing sampling, the interference of human factors on the evaluation results can be eliminated, and the accuracy of the evaluation method of the present invention can be improved; compared with Example 1, Example 6 can be used for subsequent engineering construction by classifying the safety level of soil samples. Improve reliable theoretical guidance; compared with Examples 1-6, Example 7 integrates and optimizes various favorable conditions, so that the evaluation method of the present invention is more accurate.

Claims (5)

1. A method for evaluating a repaired polluted site based on engineering safety evaluation is characterized by comprising the following steps:

s1, collecting samples;

s11, carrying out grid sampling and point distribution on the repaired polluted site, controlling the grid spacing to be 20-35m, the sampling depth to be 1-6m and the sampling amount to be 8-15g, carrying out soil sample collection, then carrying out air drying on each collected soil sample under a ventilation condition, and carrying out screening and impurity removal through a 50-80 mesh screen for later use;

s12, detecting the depth of the underground water level of the repaired polluted site, then establishing 15-30 underground water detection wells with the interval of 12-45m in the polluted site, performing well washing operation on each underground water detection well, and finally performing underground water sample collection;

s2, detecting a sample;

s21, respectively detecting the physical and mechanical indexes of the foundation soil of each soil sample obtained in the step S11 and the corrosivity detection indexes of the soil samples; the physical and mechanical indexes of the foundation soil of the soil sample comprise: characteristic value of bearing capacity of the foundation, water content, specific gravity, compression coefficient, compression modulus, internal friction angle and cohesion; the soil sample corrosivity detection indicators include: pH, Ca ²⁺ 、Mg ²⁺ 、Cl ^- 、SO ₄ ^2- 、HCO ₃ ^- 、CO ₃ ^2- Lyotropic salts, redox potential, polarization current density, resistivity and mass loss;

s22, respectively detecting the corrosivity detection indexes of the underground water samples obtained in the step S12, wherein the corrosivity detection indexes of the underground water samples comprise: pH, Ca ²⁺ 、Mg ²⁺ 、Cl ^- 、SO ₄ ^2- 、HCO ₃ ^- 、CO ₃ ^2- Aggressive CO ₂ Free CO ₂ 、NH ₄ ⁺ 、OH ^- Total degree of mineralization;

s3, establishing an evaluation model;

s31, calculating a damage quotient of the repaired polluted site to the building engineering according to the physical and mechanical indexes of the foundation soil of the soil sample in the step S21, the corrosivity detection indexes of the soil sample and the corrosivity detection indexes of the groundwater sample in the step S22, and performing risk characterization;

s32, dividing the engineering safety level into 4 levels, namely I level, II level, III level and IV level, by combining with the use planning of the polluted site; determining a safety evaluation standard of a polluted site according to a data index corresponding to the engineering safety level, wherein the data index comprises a concrete structure corrosion rate and a steel structure corrosion rate; wherein, the corrosion rate of the concrete structure corresponding to the I-level engineering safety is 12-15g/dm ² A, the corrosion rate of the steel structure is 8-10g/dm ² A; the corrosion rate of the concrete structure corresponding to the level II engineering safety is 9-12g/dm ² A, the corrosion rate of the steel structure is 6-8g/dm ² A; the corrosion rate of the concrete structure corresponding to the III-grade engineering safety is 6-9g/dm ² A, the corrosion rate of the steel structure is 4-6g/dm ² A; the corrosion rate of the concrete structure corresponding to the IV-level engineering safety is 3-6g/dm ² A, the corrosion rate of the steel structure is 2-4g/dm ² .a；

S4, outputting a result;

calculating the corrosion rate of the repaired polluted site to a concrete structure and a steel structure, and judging whether the pollution risk of each sampling point of the repaired polluted site can be received according to the safety evaluation standard in the step S32; if the pollution risk is acceptable, the assessment is finished; and if the pollution risk is unacceptable, making a corresponding pollution site remediation scheme.

In the step S12, collecting an underground water sample after the water body in the underground water detection well is stabilized for 5-12 h; meanwhile, in the process of collecting the underground water sample, the sampling depth is 0.4-0.7m greater than the underground water level depth of the repaired polluted site;

after the step S2 is completed, performing data descriptive statistical analysis on the physical and mechanical indexes of the foundation soil of the soil sample, the corrosivity detection indexes of the soil sample and the corrosivity detection indexes of the underground water sample, wherein the main measurement indexes are skewness, kurtosis and variation coefficient, and performing normal distribution judgment;

before the step S11, firstly determining the rock and soil distribution condition of the repaired polluted site, after the step S11 is completed, carrying out classified statistics on the collected soil samples according to the rock and soil distribution condition of the repaired polluted site to obtain various rock and soil layer data samples, and interpolating data of other unmeasured positions from the various rock and soil layer data samples by adopting an inverse distance weighting method to obtain sample data of each position of various rock and soil layers;

in step S21, after the foundation soil physical and mechanical indexes of the soil sample and the corrosivity detection indexes of the soil sample are detected, the sample data detection values of the same type of rock-soil layer are summed and averaged, and the obtained average value is used as the sample detection value of the corresponding sampling point of the corresponding rock-soil layer.

2. The method for evaluating the repaired contaminated site based on the engineering safety evaluation of claim 1, wherein in the step S12, the amount of the washing water used in the well washing process of the groundwater detection well is 4-8 times of the volume of the groundwater detection well.

3. The method for evaluating the repaired pollution site based on the engineering safety evaluation as claimed in claim 1, wherein after step S4 is completed, the pollution risk unacceptable area is subjected to supplementary sampling and data detection.

4. The method for evaluating the repaired contaminated site based on the engineering safety evaluation of claim 1, wherein after the completion of the step S2, the indexes of the physical mechanics of the foundation soil of the soil sample, the indexes of the corrosivity detection of the soil sample and the indexes of the corrosivity detection of the groundwater sample are ranked.

5. The method for evaluating the repaired contaminated site based on the engineering safety evaluation as claimed in claim 1, wherein in step S21, the soil sample is detected according to the Tessier continuous extraction procedure, and after the detection, the soil sample is graded in safety.