A refined sampling survey method based on green remediation and regeneration of contaminated soil

Abstract

The present invention provides a refined sampling investigation method based on green remediation and regeneration of contaminated soil, including: step 10, conducting on-site surveys to determine the boundaries of the contaminated site and the boundaries of the production area; step 20, building wells outside the boundaries of the contaminated site to detect and obtain groundwater flow field information; step 30, laying out test points, measuring the foundation bearing capacity within the preset depth of the test points; step 40, laying out sampling points, and obtaining the sampling parameters of each layer within the preset depth of the sampling points according to the foundation bearing capacity within the preset depth of the testing points; step 50, performing soil drilling sampling according to the sampling parameters of each layer within the preset depth of the sampling points; step 60, testing soil samples to obtain the spatial distribution of site pollution. The present invention provides a refined sampling investigation method based on green remediation and regeneration of contaminated soil, which can accurately investigate and obtain the spatial distribution of site pollution and provide a reliable basis for soil remediation and regeneration.

Description

Technical Field

[0001] The present invention belongs to the technical field of contaminated soil regeneration, and in particular, relates to a refined sampling and investigation method based on green restoration and regeneration of contaminated soil. Background Art

[0002] Contaminated soil on the site poses a potential hazard to human health and the surrounding environment. Therefore, the remediation and regeneration of contaminated soil is crucial to protecting the environment, ensuring human health and the balance of the ecosystem. The detailed investigation of soil pollution on the site and the characterization of pollution distribution are the prerequisites for the green remediation and regeneration of contaminated soil on the site. At present, the investigation of soil pollution status mainly uses direct push sampling technology, which uses the gravity and hydraulic driving force of the drilling equipment to penetrate the drilling tool into the underground soil and collect soil samples, and characterizes the pollution status according to the sampling test results. However, since there is no unified standard for direct push soil sampling technology at home and abroad, the operation level of different operators is uneven, which will significantly affect the sampling quality and the representativeness of the survey results. Especially for weak and deformable soils, it is easy to cause the collected samples to show large uneven compression due to incorrect sampling parameters such as the penetration speed of the sampling drill and the percussion frequency of the sampling drill during the sampling process, which brings great difficulties to the characterization of the site pollution depth and pollution characteristics. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide a refined sampling investigation method based on green remediation and regeneration of contaminated soil, which can accurately detect the spatial distribution of site pollution and provide a reliable basis for soil remediation and regeneration.

[0004] To solve the above technical problems, the embodiments of the present invention adopt the following technical solutions:

[0005] The embodiment of the present invention provides a refined sampling investigation method based on green remediation and regeneration of contaminated soil, comprising the following steps:

[0006] Step 10, conduct on-site survey to determine the boundaries of the contaminated site and the boundaries of each production area within the contaminated site;

[0007] Step 20, building a well outside the boundary of the contaminated site, detecting the depth of the groundwater level, and obtaining groundwater flow field information of the contaminated site;

[0008] Step 30, setting up test points in the contaminated site, and detecting and obtaining the foundation bearing capacity within a preset depth of all test points;

[0009] Step 40, arranging sampling points in the contaminated site, and calculating the sampling parameters of each layer within the preset depth of the sampling point according to the foundation bearing capacity within the preset depth of the sampling point;

[0010] Step 50, drilling and sampling the soil at the sampling point according to the sampling parameters of each layer within the preset depth of the sampling point to obtain a soil sample;

[0011] Step 60, testing the soil samples to obtain the spatial distribution of site pollution.

[0012] As a further improvement of the embodiment of the present invention, a direct-push drilling rig is used for soil drilling sampling; the sampling parameters include the drilling rig penetration speed and the drilling rig knocking frequency.

[0013] As a further improvement of the embodiment of the present invention, the step 40 specifically includes:

[0014] Step 401, setting up sampling points in the contaminated site;

[0015] Step 402, selecting a test point as an associated test point of the sampling point, and calculating the sampling parameters of each layer section within the preset depth of the associated test point according to the foundation bearing capacity within the preset depth of the associated test point;

[0016] Step 403, obtaining the sampling parameters of each layer section within the preset depth of the sampling point according to the sampling parameters of each layer section within the preset depth of the associated test point.

[0017] As a further improvement of the embodiment of the present invention, step 402 specifically includes:

[0018] Step 4021, selecting a test point as an associated test point of the sampling point;

[0019] Step 4022, the preset depth is evenly divided into n layers, and according to the foundation bearing capacity within the preset depth of the associated test point, the average foundation bearing capacity of each layer of the associated test point is obtained; n represents an integer greater than or equal to 2;

[0020] Step 4023, using equation (1) to calculate the drilling rig penetration rate of each layer within the preset depth of the associated test point:

[0021] Formula (1)

[0022] In the formula, Indicates the drilling speed of the i-th layer of the associated test point, in m / min; Indicates the maximum penetration speed of the drilling rig, in m / min; It represents the average value of the foundation bearing capacity of the i-th layer segment associated with the test point, in MPa; It indicates the bearing capacity of the foundation that the drill cannot penetrate at the maximum speed under the condition of maximum power of the drill, in MPa; Indicates the preset speed coefficient, in m·min -1MPa -1 ;

[0023] Formula (2) is used to calculate the drilling rig striking frequency of each layer within the preset depth of the associated test point:

[0024] Formula (2)

[0025] In the formula, Indicates the drilling rig striking frequency of the i-th layer segment associated with the test point, in Hz; Indicates the maximum percussion frequency of the drilling rig, in Hz; It indicates the bearing capacity of the foundation that the drill can penetrate without the percussion function turned on, in MPa. It indicates the bearing capacity of the foundation that the drill can penetrate under the condition of the maximum percussion frequency of the drill, in MPa; Indicates the preset frequency coefficient, in Hz·MPa -1 .

[0026] As a further improvement of the embodiment of the present invention, step 402 further includes:

[0027] Step 4024, based on the groundwater flow field information, the layer segment where the groundwater level is located is divided into two layers with the groundwater level as the boundary, so that the preset depth is divided into n+1 layers; adjust the sampling parameters of the n+1 layers within the preset depth of the associated test point.

[0028] As a further improvement of the embodiment of the present invention, the adjusting of the sampling parameters of n+1 layers within the preset depth of the associated test point specifically includes:

[0029] Formula (3) is used to calculate the adjustment coefficient of each layer within the preset depth of the associated test point:

[0030] Formula (3)

[0031] In the formula, represents the j-th layer adjustment coefficient of the associated test point, Indicates the preset formation water level adjustment coefficient; Indicates the preset drilling rig diameter adjustment coefficient, in cm -1 ; Indicates the drill bit diameter of the drilling rig, in cm; Indicates the diameter of the drill bit of the reference drill, in cm; ;

[0032] Formula (4) is used to calculate the drilling rig penetration speed of each layer within the preset depth of the adjusted associated test point:

[0033] Formula (4)

[0034] In the formula, Indicates the drilling rig penetration speed of the jth layer within the preset depth of the adjusted associated test point, in m / min; It represents the drilling speed of the original layer corresponding to the jth layer, in m / min;

[0035] Formula (5) is used to calculate the drilling rig striking frequency of each layer within the preset depth of the adjusted associated test point:

[0036] Formula (5)

[0037] In the formula, It represents the drilling rig striking frequency of the jth layer within the preset depth of the adjusted associated test point, in Hz; It represents the drilling rig striking frequency of the original layer segment corresponding to the j-th layer segment, in Hz.

[0038] As a further improvement of the embodiment of the present invention, The value range is 0.2~0.6, The value range is 60 to 140.

[0039] As a further improvement of the embodiment of the present invention, in step 4022, if the sampling point is located in the production area, the depth of each layer section is 0.5 to 1 m; otherwise, the depth of each layer section is 1 to 2 m.

[0040] As a further improvement of the embodiment of the present invention, in step 403, based on the sampling parameters of each layer segment within the preset depth of the associated test point, an interpolation method or an outer edge method is used to obtain the sampling parameters of each layer segment within the preset depth of the sampling point.

[0041] As a further improvement of an embodiment of the present invention, the foundation bearing capacity is cone tip resistance, side wall resistance or total penetration resistance.

[0042] Compared with the prior art, the technical solution of the present invention has the following beneficial effects:

[0043] (1) The present invention provides a refined sampling survey method based on green remediation and regeneration of contaminated soil. A plurality of test points are arranged in a contaminated site to detect the bearing capacity of the foundation of all the test points. After the sampling points are arranged, the sampling parameters of different depth sections of the test points associated with the sampling points are calculated. Then, based on the sampling parameters of different depth sections of the associated test points, the sampling parameters of different depth sections of the sampling points are calculated. The soil of different depth sections of the sampling points is drilled and sampled using different sampling parameters.

[0044] During the sampling process of the drilling rig, the squeezing and cutting effects of the drilling tool and the surrounding soil will cause the collected soil samples to produce compression deformation, and the foundation bearing capacity level is directly related to the sample deformation. Generally, the complex sedimentation process of the natural soil layer causes significant differences in the foundation bearing capacity of the soil at different depths. In addition, the presence of high-concentration pollutants further aggravates the spatial variability of the foundation bearing capacity. The method of the present invention adopts sampling parameters that are suitable for the foundation bearing capacity level of this layer section for sampling in the layered section, which can effectively reduce the squeezing and cutting effects of the sampling drill and the soil, and reduce the energy input of the drill to the collected samples during the sampling process, thereby reducing the compression deformation of the soil samples caused by soil heterogeneity. The method of the present invention can significantly reduce the compression rate of soil samples, thereby improving the fidelity of the samples, and then a more accurate spatial distribution of site pollution can be obtained based on the sample detection results, providing a reliable basis for subsequent soil remediation and regeneration.

[0045] (2) The method of the present invention adopts a direct-push drilling rig to drill and sample the soil. The corresponding sampling parameters include the drilling rig penetration speed and the drilling rig percussion frequency. The drilling rig penetration speed and the drilling rig percussion frequency of the corresponding depth section are calculated according to the foundation bearing capacity of the layer sections at different depths. During the drilling and sampling process, different drilling rig penetration speeds and drilling rig percussion frequencies are used for the layers at different depths. Compared with the traditional sampling method, that is, sampling at the maximum drilling rig penetration speed, the soil compression rate collected by the method of the present invention is significantly lower than that of the traditional sampling method.

[0046] (3) The method of the present invention obtains the groundwater flow field information of the contaminated site by building wells around the contaminated site and detecting the depth of the groundwater level. The layer sections that cross the groundwater level are further segmented based on the groundwater level, and the sampling parameters of all layers are adjusted in combination with the drill bit diameter of the drilling rig. Since the soil moisture content is significantly correlated with the strength parameters of clay soil such as cohesion and friction angle, and has a significant impact on the compression deformation of the collected soil samples, the method of the present invention considers the influence of soil moisture content at different depths on the friction resistance between the soil and the drill bit, and divides the sampling parameters into those above the groundwater level and those below the groundwater level for separate calculation and adjustment, thereby achieving the most accurate restoration of the collected soil samples.

[0047] (4) When conducting on-site surveys, the method of the present invention determines the boundaries of each production area in the contaminated site and divides the depth into layers. If the sampling point is located in the production area, the depth of each layer is 0.5 to 1 m, otherwise the depth of each layer is 1 to 2 m, that is, the number of layers of the sampling points in the production area is more than that of the sampling points in the non-production area. The production area is where the pollution source is located. Compared with the non-production area, the soil pollutant concentration is higher and the spatial deformability is greater. In addition, the production area usually undergoes foundation treatment, which is different from the original geological stratification in the site. When the method of the present invention samples the sampling points located in the production area, by appropriately reducing the depth of each layer, the deformation of the collected samples can be significantly reduced, thereby improving the accuracy of the pollution distribution depiction of the collected soil samples. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 is a flow chart of a refined sampling survey method according to an embodiment of the present invention;

[0049] Figure 2 It is a schematic diagram of determining the boundary of the contaminated site, the boundary of the production area, and the groundwater flow field obtained by well construction and detection in a specific example of the present invention;

[0050] Figure 3 It is a schematic diagram of the layout of the test points and sampling points in a specific example of the present invention;

[0051] Figure 4 yes Figure 3 A-A' cross-sectional view;

[0052] Figure 5 The soil 1,4-dichlorobenzene obtained by the specific example of the present invention and the traditional method is Figure 3 Distribution diagram of the B-B' section.

[0053] In the figure: the boundary 101 of the contaminated site, the boundary 102 of the production area, the boundary 103 of the artificial foundation, the groundwater level monitoring well 201, the groundwater level line 202, the first test point 301, the second test point 302, the first sampling point 401, the second sampling point 402, the third sampling point 403, the fourth sampling point 404, the fill layer 501, the silty clay layer 502, the silty clay and silty sand layer 503, the groundwater level 504, the soil 1,4-dichlorobenzene distribution boundary 601 obtained by the specific example of the present invention, and the soil 1,4-dichlorobenzene distribution boundary 602 obtained by the traditional method. DETAILED DESCRIPTION

[0054] The technical solution of the present invention is described in detail below.

[0055] The embodiment of the present invention provides a refined sampling survey method based on green remediation and regeneration of contaminated soil. Figure 1 As shown, the following steps are included:

[0056] Step 10: Conduct on-site survey to determine the boundaries of the contaminated site and the boundaries of each production area within the contaminated site.

[0057] Step 20, wells are built around the periphery of the contaminated site. Specifically, groundwater monitoring wells are set up upstream and downstream of the groundwater flow direction of the contaminated site, and groundwater monitoring wells are also set up on both sides perpendicular to the groundwater flow direction. The groundwater level depth is detected to obtain the groundwater flow field information of the contaminated site.

[0058] Step 30, test points are arranged in the contaminated site. In order to avoid the spread of pollutants, test points are set in non-production areas. The number of test points is determined according to the size of the contaminated site. Test points can be set at the corners of the boundary of the contaminated site, or around the boundary of the contaminated site, or in non-production areas of the contaminated site.

[0059] The foundation bearing capacity within the preset depth of all test points is detected. Among them, the foundation bearing capacity is the cone tip resistance, the side wall resistance or the total penetration resistance. In this embodiment, the cone tip resistance is preferably used as the foundation bearing capacity, which can be obtained by double-bridge probe testing. In the early stage, the site is explored to predict the depth of soil contamination and set a preset depth, which is also the sampling depth.

[0060] Step 40, arrange sampling points in the contaminated site, and calculate the sampling parameters of each layer within the preset depth of the sampling point according to the foundation bearing capacity within the preset depth of the sampling point.

[0061] The embodiment of the present invention adopts a direct-push drilling rig to perform soil drilling sampling, and the sampling parameters include the drilling rig penetration speed and the drilling rig knocking frequency.

[0062] Step 40 specifically includes:

[0063] Step 401, setting up sampling points in the contaminated site.

[0064] Step 402: Select a test point related to the sampling point as an associated test point of the sampling point, and calculate the sampling parameters of each layer within the preset depth of the associated test point according to the bearing capacity of the foundation within the preset depth of the associated test point.

[0065] Specifically include:

[0066] Step 4021, selecting associated test points for each sampling point.

[0067] When selecting for a single sampling point, one of the methods is to select 2 or more test points around the sampling point as associated test points of the sampling point based on the principle of being closest to the sampling point.

[0068] Step 4022, divide the preset depth (in meters) of the associated test point into n layers, and calculate the average foundation bearing capacity of each layer according to the foundation bearing capacity within the preset depth of the associated test point; n represents an integer greater than or equal to 2. Preferably, n=4, 5, 6, 7 or 8.

[0069] Preferably, if the sampling point is located in the production area, the depth of each layer section is 0.5 to 1m; otherwise, the depth of each layer section is 1 to 2m. The number of layers divided into the sampling points in the production area is more than the number of layers divided into the sampling points in the non-production area. For example, the preset depth is 6m, that is, the maximum depth of downward sampling is 6m. If the sampling point is located in the production area, the preset depth of the sampling point and its associated test point is divided into 8 layers, and the depth of each layer section is 0.75m. If the sampling point is located in the non-production area, the preset depth of the sampling point and its associated test point is divided into 4 layers, and the depth of each layer section is 1.5m.

[0070] Step 4023, using formula (1) to calculate the drilling rig penetration speed of each layer within the preset depth of the associated test point:

[0071] Formula (1)

[0072] In the formula, Indicates the drilling speed of the i-th layer of the associated test point, in m / min; Indicates the maximum penetration speed of the drilling rig, in m / min; It represents the average value of the foundation bearing capacity of the i-th layer segment associated with the test point, in MPa; It indicates the bearing capacity of the foundation that the drill cannot penetrate at the maximum speed under the condition of maximum power of the drill, in MPa; Indicates the preset speed coefficient, in m·min -1 MPa -1 Preferably, The value range is 0.2~0.6.

[0073] Formula (2) is used to calculate the drilling rig striking frequency of each layer within the preset depth of the associated test point:

[0074] Formula (2)

[0075] In the formula, Indicates the drilling rig striking frequency of the i-th layer segment associated with the test point, in Hz; Indicates the maximum percussion frequency of the drilling rig, in Hz; It indicates the bearing capacity of the foundation that the drill can penetrate without the percussion function turned on, in MPa. It indicates the bearing capacity of the foundation that the drill can penetrate under the condition of the maximum percussion frequency of the drill, in MPa; Indicates the preset frequency coefficient, in Hz·MPa -1 Preferably, The value range is 60 to 140.

[0076] Step 4024: Based on the groundwater flow field information, the layer segment where the groundwater level is located is further divided into two sub-layer segments with the groundwater level as the boundary, thereby obtaining n+1 layer segments. For example, the original layer segment is divided into 4 layers, and the second layer segment crosses the groundwater level. The second layer segment is further divided into 2 sub-layer segments, thereby having a total of 5 layers. Moreover, the first layer segment corresponds to the original first layer segment, the second layer segment corresponds to the original second layer segment, the third layer segment corresponds to the original third layer segment, and the fifth layer segment corresponds to the original fourth layer segment.

[0077] Adjust the sampling parameters for all layers. Specifically:

[0078] Formula (3) is used to calculate the adjustment coefficient of each layer within the preset depth of the associated test point:

[0079] Formula (3)

[0080] In the formula, represents the j-th layer adjustment coefficient of the associated test point, Indicates the preset formation water level adjustment coefficient; Indicates the preset drilling rig diameter adjustment coefficient, in cm -1 ; Indicates the drill bit diameter of the drilling rig, in cm; Indicates the diameter of the drill bit of the reference drill, in cm; .

[0081] Formula (4) is used to calculate the drilling rig penetration speed of each layer within the preset depth of the adjusted associated test point:

[0082] Formula (4)

[0083] In the formula, Indicates the drilling rig penetration speed of the jth layer within the preset depth of the adjusted associated test point, in m / min; It represents the drilling rig penetration speed of the original layer section corresponding to the j-th layer section, in m / min.

[0084] Still taking the above example, , , , , .

[0085] Formula (5) is used to calculate the drilling rig striking frequency of each layer within the preset depth of the adjusted associated test point:

[0086] Formula (5)

[0087] In the formula, It represents the drilling rig striking frequency of the jth layer within the preset depth of the adjusted associated test point, in Hz; It represents the drilling rig striking frequency of the original layer segment corresponding to the j-th layer segment, in Hz.

[0088] Still taking the above example, , , , , .

[0089] Step 403, based on the adjusted sampling parameters of each layer segment within the preset depth of the associated test point, the sampling parameters of each layer segment within the preset depth of the sampling point are calculated by using an interpolation method or an outer edge method.

[0090] Step 50, according to the sampling parameters of each layer section within the preset depth of the sampling point, soil drilling sampling is performed at the sampling point to obtain a soil sample.

[0091] Step 60, testing the soil samples to obtain the spatial distribution of site pollution.

[0092] A specific example is provided below.

[0093] Conduct site surveys, such as Figure 2 As shown, the boundary 101 of the contaminated site, the boundaries 102 of each production area in the contaminated site, and the boundary 103 of the artificial foundation are determined. Three groundwater level monitoring wells 201 are set up upstream and downstream of the groundwater flow outside the boundary of the contaminated site, and two groundwater level monitoring wells 201 are set up on both sides perpendicular to the groundwater flow to observe the groundwater level depth and depict the groundwater isowater level line 202.

[0094] Four test points were set up at the corners within the boundary of the contaminated site, and a total of 13 sampling points were set up in the production area and non-production area of ​​the contaminated site, such as Figure 3 According to the regional hydrogeological conditions and the bottom distribution survey of the surrounding plots, three strata are exposed within the preset depth of 6m in the contaminated site, namely, the fill layer 501, the silty clay layer 502 and the silty clay and silty sand layer 503. Figure 4 The cone tip resistance obtained by the double bridge probe test is used to characterize the foundation bearing capacity, and the cone tip resistance of four test points is obtained by the test.

[0095] An associated test point is selected for the first sampling point 401 . The first sampling point 401 is closer to the line connecting the first test point 301 and the second test point 302 . Therefore, the first test point 301 and the second test point 302 are selected as associated test points of the first sampling point 401 .

[0096] The first sampling point 401 is located in the non-production area, and 6m is divided into 4 layers, each with a depth of 1.5m. The first test point 301 has an average value of cone tip resistance of 1.59MPa, 0.83MPa, 1.71MPa, and 1.77MPa from top to bottom along the depth direction of the 4 layers, and the groundwater level is 1.65m deep. The second test point 302 has an average value of cone tip resistance of 1.61MPa, 0.85MPa, 1.89MPa, and 1.73MPa from top to bottom along the depth direction of the 4 layers, and the groundwater level is 1.57m deep.

[0097] The drilling rig penetration rate of each layer within 6 m of the first test point 301 is calculated using formula (1). In formula (1), =2m / min, =1.3MPa, =0.35m / (min·MPa), and the drilling rig penetration speeds of the four layers from top to bottom along the depth direction are 1.90m / min, 2.00m / min, 1.86m / min, and 1.84m / min respectively. The drilling rig percussion frequency of each layer within 6m of the first test point 301 is calculated using formula (2). In formula (2), =80Hz, =1.3MPa, =2.1MPa, =100Hz / MPa, and the drilling rig percussion frequencies of the four layers from top to bottom in the depth direction are 29Hz, 0Hz, 41Hz, and 47Hz respectively. From top to bottom, the second layer crosses the groundwater level. The part above the groundwater level of the second layer is the first sublayer, and the part below the groundwater level is the second sublayer. Thus, 6m is divided into five layers from top to bottom, namely the first layer, the first sublayer of the second layer, the second sublayer of the second layer, the third layer, and the fourth layer. The adjustment coefficients of the five layers from top to bottom are calculated using formula (3). In formula (3), =-0.08, =0.03, =35cm, =45cm, and the adjustment coefficients of the five layers from top to bottom are 1.22, 1.22, 1.30, 1.30, and 1.30, respectively. The drilling tool penetration speeds of the five layers from top to bottom are calculated by formula (4) as 2.32m / min, 2.44m / min, 2.60m / min, 2.41m / min, and 2.39m / min, respectively. The drilling tool percussion frequencies of the five layers from top to bottom are calculated by formula (5) as 35Hz, 0Hz, 0Hz, 53Hz, and 61Hz, respectively.

[0098] Using the same method, it is calculated that the drill penetration speeds of the five layers from top to bottom at the second test point 302 are 2.31m / min, 2.44m / min, 2.60m / min, 2.33m / min, and 2.40m / min, respectively, and the drill striking frequencies of the five layers from top to bottom are 38Hz, 0Hz, 0Hz, 77Hz, and 56Hz, respectively.

[0099] The straight-line distances between the first sampling point 401 and the first test point 301 and the second test point 302 are 23m and 106m respectively. The groundwater level depth of the first sampling point 401 is: 1.65×23 / (23+106)+1.57×106 / (23+106)=1.58m. The drilling tool penetration speed of the first layer section from top to bottom of the first sampling point 401 is: 2.32×23 / (23+106)+2.31×106 / (23+106)=2.31m / min. The same method is used to calculate the drilling tool penetration speed of the first sub-layer section of the second layer, the second sub-layer section of the second layer, the third layer and the fourth layer, and the drilling tool penetration speed of the first sampling point 401 from top to bottom is 2.31m / min, 2.44m / min, 2.60m / min, 2.35m / min, 2.40m / min. The same method is used to calculate the drilling tool percussion frequency of the first sampling point 401 from top to bottom. The five layers are 37Hz, 0Hz, 0Hz, 73Hz, and 57Hz. In order to facilitate the operation of the drilling rig by the on-site personnel, the maximum percussion frequency is adjusted and optimized to an integer multiple of 5Hz (rounded down). After optimization, the drilling tool percussion frequency of the first sampling point 401 from top to bottom is 35Hz, 0Hz, 0Hz, 70Hz, and 55Hz.

[0100] Then, an associated test point is selected for the second sampling point 402. The second sampling point 402 is closer to the line connecting the first test point 301 and the second test point 302, so the first test point 301 and the second test point 302 are selected as the associated test points of the second sampling point 402. The straight-line distances between the second sampling point 402 and the first test point 301 and the second test point 302 are 41 m and 133 m respectively.

[0101] The second sampling point 402 is located in the production area, dividing 6m into 8 layers, and the depth of each layer is 0.75m. The first test point 301, from top to bottom along the depth direction, the average values ​​of the cone tip resistance of the 8 layers are 1.58MPa, 1.63MPa, 0.81MPa, 0.87MPa, 1.75MPa, 1.69MPa, 1.77MPa, 1.77MPa, and the groundwater level is 1.65m. The second test point 302, from top to bottom along the depth direction, the average values ​​of the cone tip resistance of the 8 layers are 1.60MPa, 1.61MPa, 0.84MPa, 0.85MPa, 1.76MPa, 1.70MPa, 1.79MPa, 1.75MPa, and the groundwater level is 1.57m.

[0102] Using the same method, the groundwater level depth of the first sampling point 401 is calculated as: 1.65×41 / (41+133)+1.57×133 / (41+133)=1.58m. The drilling tool penetration speeds of the 9 layers from top to bottom of the second sampling point 402 are calculated to be 2.31m / min, 2.31m / min, 2.44m / min, 2.60m / min, 2.60m / min, 2.39m / min, 2.40m / min, 2.41m / min, and 2.38m / min, respectively, and the drilling tool percussion frequencies of the 9 layers from top to bottom of the second sampling point 402 are 35Hz, 35Hz, 0Hz, 0Hz, 0Hz, 55Hz, 50Hz, 60Hz, and 55Hz, respectively.

[0103] The sampling parameters of all sampling points in the contaminated site are calculated, and then sample collection at all sampling points is completed based on the sampling parameters of each layer of each sampling point.

[0104] The sample compression rate of each sampling point is calculated using formula (6):

[0105] Formula (6)

[0106] In the formula, L s Indicates the length of the sampling tube, in m; L 0 represents the length of the soil sample collected in the sampling tube, in meters.

[0107] The sample compression rate of the first sampling point 401 is 5.6%, and the sample compression rate of the second sampling point 402 is 9.3%.

[0108] The soil 1,4-dichlorobenzene concentration of the samples at the first sampling point 401, the third sampling point 403 and the fourth sampling point 404 is detected, and the distribution of 1,4-dichlorobenzene in the soil at the B-B' of the profile where the three test points are located is plotted, see Figure 5The soil 1,4-dichlorobenzene distribution boundary 601 obtained by investigating the specific example of the present invention.

[0109] The conventional method was used to sample the point in the middle of the line connecting the first test point 301 and the first sampling point 401, using the same direct-push drill. The sampling was performed at the maximum penetration speed of the drill (3 m / min). When the drill could not penetrate, the drill percussion mode was turned on and the percussion frequency was kept at the maximum value (80 Hz).

[0110] After the collection is completed, the sample compression rate at this point is calculated to be 19.2%. The soil 1,4-dichlorobenzene concentration of the sample is tested and the distribution of soil 1,4-dichlorobenzene in the B-B' section of the profile is plotted. Figure 5 The distribution boundary of 1,4-dichlorobenzene in soil obtained by traditional method investigation 602.

[0111] By comparison, it can be seen that the compression rate of the soil sample obtained by the traditional method is 3.4 times that of the soil sample obtained by the specific example of the present invention. The method of the embodiment of the present invention can effectively reduce the compression rate of the soil sample. The smaller the compression rate, the greater the fidelity. Figure 5 It can be seen that due to the low compression rate of the method of the embodiment of the present invention, the boundary of 1,4-dichlorobenzene in the soil is closer to the actual pollution situation; while the high compression deformation of the soil sample of the traditional method causes the overall displacement of the boundary of 1,4-dichlorobenzene in the soil to a greater depth, which greatly deviates from the actual pollution situation.

[0112] The basic principles, main features and advantages of the present invention are shown and described above. Those skilled in the art should understand that the present invention is not limited to the above specific embodiments, and the descriptions in the above specific embodiments and the specification are only for further illustrating the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, and these changes and improvements all fall within the scope of the present invention claimed for protection.

Claims

1. A refined sampling survey method based on green remediation and regeneration of contaminated soil, characterized in that: The following steps are involved: Step 10, conduct on-site survey to determine the boundaries of the contaminated site and the boundaries of each production area within the contaminated site; Step 20, building a well outside the boundary of the contaminated site, detecting the depth of the groundwater level, and obtaining groundwater flow field information of the contaminated site; Step 30, setting up test points in the contaminated site, and detecting and obtaining the foundation bearing capacity within a preset depth of all test points; Step 40, arranging sampling points in the contaminated site, and calculating the sampling parameters of each layer within the preset depth of the sampling point according to the foundation bearing capacity within the preset depth of the sampling point; Step 50, drilling and sampling the soil at the sampling point according to the sampling parameters of each layer within the preset depth of the sampling point to obtain a soil sample; Step 60, testing the soil samples to obtain the spatial distribution of site pollution; The sampling parameters include drilling rig penetration speed and drilling rig percussion frequency; The step 40 specifically includes: Step 401, setting up sampling points in the contaminated site; Step 402, selecting a test point as an associated test point of the sampling point, and calculating the sampling parameters of each layer section within the preset depth of the associated test point according to the foundation bearing capacity within the preset depth of the associated test point; Step 403, obtaining the sampling parameters of each layer section within the preset depth of the sampling point according to the sampling parameters of each layer section within the preset depth of the associated test point; The step 402 specifically includes: Step 4021, selecting a test point as an associated test point of the sampling point; Step 4022, the preset depth is evenly divided into n layers, and according to the foundation bearing capacity within the preset depth of the associated test point, the average foundation bearing capacity of each layer of the associated test point is obtained; n represents an integer greater than or equal to 2; Step 4023, using equation (1) to calculate the drilling rig penetration rate of each layer within the preset depth of the associated test point: Formula (1) In the formula, Indicates the drilling speed of the i-th layer of the associated test point, in m / min; Indicates the maximum penetration speed of the drilling rig, in m / min; It represents the average value of the foundation bearing capacity of the i-th layer segment associated with the test point, in MPa; It indicates the bearing capacity of the foundation that the drill cannot penetrate at the maximum speed under the condition of maximum power of the drill, in MPa; Indicates the preset speed coefficient, in m·min -1 MPa -1 ; Formula (2) is used to calculate the drilling rig striking frequency of each layer within the preset depth of the associated test point: Formula (2) In the formula, Indicates the drilling rig striking frequency of the i-th layer segment associated with the test point, in Hz; Indicates the maximum percussion frequency of the drilling rig, in Hz; It indicates the bearing capacity of the foundation that the drill can penetrate without the percussion function turned on, in MPa. It indicates the bearing capacity of the foundation that the drill can penetrate under the condition of the maximum percussion frequency of the drill, in MPa; Indicates the preset frequency coefficient, in Hz·MPa -1 .

2. The refined sampling survey method according to claim 1 is characterized in that: A direct-push drilling rig was used for soil drilling and sampling.

3. The refined sampling survey method according to claim 1 is characterized in that: The step 402 further includes: Step 4024, based on the groundwater flow field information, the layer segment where the groundwater level is located is divided into two layers with the groundwater level as the boundary, so that the preset depth is divided into n+1 layers; adjust the sampling parameters of the n+1 layers within the preset depth of the associated test point.

4. The refined sampling survey method according to claim 3 is characterized in that: The step of adjusting the sampling parameters of n+1 layers within the preset depth of the associated test point specifically includes: Formula (3) is used to calculate the adjustment coefficient of each layer within the preset depth of the associated test point: Formula (3) In the formula, represents the j-th layer adjustment coefficient of the associated test point, Indicates the preset formation water level adjustment coefficient; Indicates the preset drilling rig diameter adjustment coefficient, in cm -1 ; Indicates the drill bit diameter of the drilling rig, in cm; Indicates the diameter of the drill bit of the reference drill, in cm; ; Formula (4) is used to calculate the drilling rig penetration speed of each layer within the preset depth of the adjusted associated test point: Formula (4) In the formula, Indicates the drilling rig penetration speed of the jth layer within the preset depth of the adjusted associated test point, in m / min; It represents the drilling speed of the original layer corresponding to the jth layer, in m / min; Formula (5) is used to calculate the drilling rig striking frequency of each layer within the preset depth of the adjusted associated test point: Formula (5) In the formula, It represents the drilling rig striking frequency of the jth layer within the preset depth of the adjusted associated test point, in Hz; It represents the drilling rig striking frequency of the original layer segment corresponding to the j-th layer segment, in Hz.

5. The refined sampling survey method according to claim 1 is characterized in that: The value range is 0.2~0.6, The value range is 60 to 140.

6. The refined sampling survey method according to claim 1 is characterized in that: In step 4022, if the sampling point is located in the production area, the depth of each layer section is 0.5 to 1 m; otherwise, the depth of each layer section is 1 to 2 m.

7. The refined sampling survey method according to claim 1 is characterized in that: In step 403, based on the sampling parameters of each layer segment within the preset depth of the associated test point, the sampling parameters of each layer segment within the preset depth of the sampling point are obtained by using an interpolation method or an outer edge method.

8. The refined sampling survey method according to claim 1 is characterized in that: The foundation bearing capacity is cone tip resistance, side wall resistance or total penetration resistance.

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