Determination method for engineering characteristic parameters of deep sand gravel damming material

Abstract

The invention discloses a method for determining engineering characteristic parameters of a deep sand gravel damming material, belongs to the technical field of geological exploration, and can solve the problem that an existing exploration method cannot comprehensively reflect the real condition of particle distribution of a material field. The method comprises the following steps: S1, in the excavation process of a plurality of sample testing structures in a material yard area, collecting excavation materials and side wall images of the sample testing structures according to excavation cycles, and carrying out a full-section screening test on the excavation materials of each cycle to obtain a grain composition curve of the excavation materials of each cycle; s2, determining the uniformity index of the material field area according to all the back excavation materials and the grain composition curve and the side wall image of the back excavation materials; s3, when the homogeneity index meets a preset condition, the material field area is partitioned according to the grain composition curves and the side wall images of all the excavation materials of the return times, and a plurality of geological areas are obtained; and S4, performing an engineering characteristic test on each geological area to obtain engineering characteristic parameters of sand gravel in each geological area. The method is used for determining the engineering characteristics of the damming material.

Description

Technical Field

[0001] The invention relates to a method for determining engineering characteristic parameters of thick gravel dam-building materials, belonging to the technical field of geological exploration. Background Art

[0002] Gravel is widely used as dam filling material due to its high deformation resistance and low mining cost. For the engineering geological survey of deep gravel layers, the main technical means currently used include core drilling, shaft exploration and geophysical exploration. However, the above methods all have certain technical limitations: in the core drilling method, the gravel layer has a loose accumulation structure and often contains boulder interlayers, which leads to a significant reduction in the core collection rate in the drilling process. It is also limited by the conventional borehole diameter (usually 75mm ~150mm), and the sampling and screening are highly random, which cannot fully reflect the actual situation of the material field particle distribution; in the shaft exploration method, the shaft depth is generally limited, and the purpose of exposing the useful material stratum cannot be achieved; although the geophysical exploration method can effectively explore the spatial distribution of the overburden layer, it is difficult to quantitatively characterize its engineering characteristics due to the multi-solution constraint. Summary of the invention

[0003] The invention provides a method for determining engineering characteristic parameters of deep gravel dam-building materials, which can solve the problem that the existing survey method cannot fully reflect the real situation of particle distribution in the material field and cannot reveal the useful material strata.

[0004] The present invention provides a method for determining engineering characteristic parameters of deep gravel dam-building materials, the method comprising:

[0005] S1. During the excavation of multiple sampling structures in the material field, images of the side walls of the excavated materials and the sampling structures are collected according to the number of excavation rounds, and a full-section screening test is performed on the excavated materials of each round to obtain the particle gradation curve of the excavated materials of each round;

[0006] S2. Determine the uniformity index of the material field area according to all the excavated materials and their particle gradation curves and the side wall images of all the excavated materials;

[0007] S3. When the uniformity index meets the preset conditions, the material field is divided into zones according to the particle grading curves of all excavated materials and the side wall images of all excavated materials to obtain multiple geological zones;

[0008] S4. Conduct engineering property tests on each geological area to obtain the engineering property parameters of sand and gravel in each geological area.

[0009] Optionally, the uniformity index includes defective particle rate, content of each particle size group of particles in the same layer, relative coarseness and fineness of particles in a single sample structure, and morphological characteristics of a particle grading curve.

[0010] Optionally, S2 specifically includes:

[0011] Determine the particle defect rate based on the excavation material for each round and the sidewall images of each round of excavation. Determine the content of each particle size group of the same-layer particles based on the particle size distribution curves of the excavation materials collected by multiple sampling structures at the same excavation height. Determine the relative coarseness of the particles of a single sampling structure based on the excavation materials collected by a single sampling structure at different excavation heights. And determine the morphological characteristics of the particle size distribution curve based on the particle size distribution curves of all rounds of excavation materials.

[0012] Optionally, S3 specifically includes:

[0013] When the particle defect rate, the content of each particle size group of the same-layer particles, the relative coarseness of the particles of a single sampling structure, and the morphological characteristics of the particle size distribution curve are all good, partition the material yard area based on the particle size distribution curves of all rounds of excavation materials and the sidewall images of all rounds of excavation to obtain multiple geological areas.

[0014] Optionally, in S3, partitioning the material yard area based on the particle size distribution curves of all rounds of excavation materials and the sidewall images of all rounds of excavation to obtain multiple geological areas specifically includes:

[0015] Determine the particle size stratification of all rounds of excavation materials based on the particle size distribution curves of all rounds of excavation materials, and determine the cementation condition and the condition of bad interlayers of all sampling structures based on the sidewall images of all rounds of excavation.

[0016] Partition the material yard area according to the particle size stratification, the cementation condition, and the condition of bad interlayers to obtain multiple geological areas.

[0017] Optionally, determining the particle size stratification of all rounds of excavation materials based on the particle size distribution curves of all rounds of excavation materials specifically means:

[0018] Divide the particle sizes of all rounds of excavation materials into the coarsest layer, the coarse layer, the medium-coarse layer, and the fine layer according to the particle size distribution curves of all rounds of excavation materials.

[0019] Optionally, the sampling structure includes multiple vertical shafts.

[0020] Optionally, the sampling structure further includes a chute that is arranged on the shore or the edge of a ditch in the material yard area and penetrates the material layer from top to bottom.

[0021] Optionally, the excavation footage of the chute and the vertical shaft is the same.

[0022] Optionally, the engineering property tests include: relative density test, consolidation test of coarse-grained soil, shear strength test of coarse-grained soil, linear stress-strain test, and permeability and permeability deformation test.

[0023] The beneficial effects that can be produced by the present invention include:

[0024] The method for determining the engineering property parameters of deep gravel and sand dam building materials provided by the present invention screens samples through full-section sampling of multiple sampling structures in the material yard area, and then determines the uniformity index of the material yard area according to the test results. When the uniformity index meets the preset conditions, the material yard area is divided according to the test results, and finally the engineering properties of each layer of gravel and sand materials are determined through tests. This can comprehensively reflect the true situation of the particle distribution in the material yard, clarify the availability of the gravel and sand layer as building materials, thus saving a large amount of investment and being beneficial to environmental protection. Description of the Drawings

[0025] Figure 1 It is a flow chart of the method for determining the engineering property parameters of deep gravel and sand dam building materials provided by the embodiment of the present invention. Detailed Embodiments

[0026] The present invention will be described in detail below with reference to the embodiments, but the present invention is not limited to these embodiments.

[0027] The embodiment of the present invention provides a method for determining the engineering property parameters of deep gravel and sand dam building materials, as Figure 1 shown, the method includes:

[0028] S1. During the excavation of multiple sampling structures in the material yard area, collect the excavation materials and the side wall images of the sampling structures according to the excavation cycles, and conduct full-section screening tests on the excavation materials of each cycle to obtain the particle size distribution curves of the excavation materials of each cycle.

[0029] Among them, the sampling structure includes multiple vertical shafts. Further, the sampling structure also includes an inclined chute arranged on the shore or the side of the ditch in the material yard area, extending from top to bottom and penetrating the material layer.

[0030] It should be noted that the above-mentioned inclined chute is usually continuously excavated on the basis of existing gullies with a certain depth on the shore or in the ditch until it reaches the same depth as the vertical shaft; during the excavation process, the excavation footage of the inclined chute and the vertical shaft is the same.

[0031] The above-mentioned vertical shaft is an ultra-deep special vertical shaft with a circular cross-section, a diameter of 1.6 m to 1.8 m, and a depth of 80 m; the excavation method of the vertical shaft is manual excavation. During the excavation process, the excavation materials are transported to the ground, collected according to the cycles, the side wall of each cycle is photographed, and after photographing, the full-section formwork of the vertical shaft wall is poured with concrete for support. In view of the high cost of the above-mentioned vertical shaft, a large inclined chute can be excavated from the top of the material layer along the shore and the side of the ditch in the material yard area, penetrating the material layer, and collecting the excavation materials and the side wall images with the same excavation footage and excavation cycles as the vertical shaft.

[0032] Perform natural grading tests on the excavated materials for each round of excavation of the test sample structure. For each test sample structure in each round of excavation, conduct a full-section screening test and take samples to determine the particle composition of the excavated materials for each round and draw the particle grading curve. Screening groups: Taking the average depth of the test sample structure as 80 m as an example, for both the vertical shaft and the inclined chute, the footage per round is 1.5 m, and 54 on-site screenings are carried out for each shaft. When encountering relatively thick interlayers (more than 50 cm thick), screen them separately, and stack the materials of each particle size separately after screening.

[0033] In practical applications, the natural density, moisture content, etc. of the excavated materials can also be measured simultaneously.

[0034] S2. Determine the homogeneity index of the material yard according to the excavated materials for all rounds, their particle grading curves, and the sidewall images of all rounds of excavation.

[0035] Among them, the homogeneity index can include the percentage of defective particles, the content of each particle size group of particles in the same layer, the relative fineness of particles of a single test sample structure, and the morphological characteristics of the particle grading curve.

[0036] S2 specifically includes:

[0037] Determine the percentage of defective particles according to the excavated materials for each round and the sidewall images of each round of excavation, determine the content of each particle size group of particles in the same layer according to the particle grading curves of the excavated materials collected at the same excavation height of multiple test sample structures, determine the relative fineness of particles of a single test sample structure according to the excavated materials collected at different excavation heights of a single test sample structure, and determine the morphological characteristics of the particle grading curve according to the particle grading curves of the excavated materials for all rounds.

[0038] In the present invention, the uniformity of the distribution of gravel particles in the stockpile area determines the availability of the gravel. The present invention innovatively proposes to use four indicators, namely, (1) the defective particle rate (including the distribution of interlayers and the maximum particle size); (2) the content of each particle size group of particles in the same layer; (3) the relative fineness of particles in a single measurement sample structure; and (4) the morphological characteristics of the particle size distribution curve, to comprehensively judge the uniformity of the distribution of gravel particles in the stockpile area. Specifically, (1) the defective particle rate (distribution of interlayers and maximum particle size): Determine whether there are sand interlayers, clay, mud interlayers, aquifers, gravel layers containing mud, cemented layers, etc. in the formation of the stockpile area based on the sidewall images, so as to determine the proportion of interlayers; Determine the content of the maximum particle size in the formation of the stockpile area based on the excavated materials; Then determine the defective particle rate based on the proportion of interlayers and the content of the maximum particle size. (2) The content of each particle size group of particles in the same layer: Determine the content of each particle size group of particles in the same layer based on the particle size distribution curves of the excavated materials collected at the same excavation height by multiple measurement sample structures; Then judge whether the content characteristics of each particle size group in a single measurement sample structure are consistent with the overall law; Whether the content characteristics of each particle size group in different thickness mining layers are consistent with the overall law; Whether there are obvious changes in the content characteristics of each particle size group in space. (3) The relative fineness of particles in a single measurement sample structure: Determine the relative fineness of particles in a single measurement sample structure based on the excavated materials collected at different excavation heights by a single measurement sample structure; Then judge whether the distribution of the relative fineness of particles in a single measurement sample structure is similar to the overall law; When mining at different elevations (thicknesses), whether the distribution of the relative fineness of each thickness layer is similar to the overall; In the spatial distribution of the stockpile area, whether there is an obvious law of fineness change in different parts. (4) The morphological characteristics of the particle size distribution curve: Whether all the particle size distribution curves are smooth and concave; Whether the characteristics of a single particle size distribution curve are similar to the overall curve characteristics.

[0039] S3. When the uniformity index meets the preset conditions, partition the stockpile area according to the particle size distribution curves of all round-trip excavated materials and the sidewall images of all round-trip excavations to obtain multiple geological areas.

[0040] S3 specifically includes:

[0041] When the defective particle rate, the content of each particle size group of particles in the same layer, the relative fineness of particles in a single measurement sample structure, and the morphological characteristics of the particle size distribution curve are all good, partition the stockpile area according to the particle size distribution curves of all round-trip excavated materials and the sidewall images of all round-trip excavations to obtain multiple geological areas.

[0042] In practical applications, when the conclusions of the four indicators, namely the defective particle rate, the content of each particle size group in the same layer of particles, the relative fineness of particles in a single test sample structure, and the morphological characteristics of the particle size distribution curve, are all good in terms of uniformity, it is determined that the uniformity of the material yard area is good. Therefore, the gravel and sand in this material yard area can be utilized, and then the zoning operation is carried out; if at least one of the four indicators, namely the defective particle rate, the content of each particle size group in the same layer of particles, the relative fineness of particles in a single test sample structure, and the morphological characteristics of the particle size distribution curve, has a conclusion of poor uniformity, it is determined that the uniformity of the material yard area is poor. Therefore, the gravel and sand in this material yard area cannot be utilized, and subsequent zoning operations and engineering property studies will not be carried out.

[0043] In S3, the material yard area is zoned based on the particle size distribution curves of all the excavated materials in each round and the sidewall images of all the excavations in each round to obtain multiple geological areas, specifically including:

[0044] First, determine the particle size stratification of all the excavated materials in each round according to the particle size distribution curves of all the excavated materials in each round, and determine the cementation situation and the presence of defective interlayers of all the test sample structures according to the sidewall images of all the excavations in each round; then, zone the material yard area according to the particle size stratification situation, the cementation situation, and the presence of defective interlayers to obtain multiple geological areas.

[0045] Among them, determining the particle size stratification of all the excavated materials in each round according to the particle size distribution curves of all the excavated materials in each round is specifically as follows: divide the particle sizes of all the excavated materials in each round into the coarsest layer, the coarse layer, the medium-coarse layer, and the fine layer according to the particle size distribution curves of all the excavated materials in each round.

[0046] In practical applications, after determining the availability of the gravel and sand in the material yard area, the material yard is zoned and studied according to the test results in S1. The main basis for zoning is: ① the particle size stratification situation, that is, the particle size distribution; ② the cementation situation, that is, whether there is cementation; ③ the presence of defective interlayers, that is, the defective interlayer rate (such as sand layers, soil layers, cemented layers, large boulders). Whether there is cementation and the defective interlayer rate are both determined according to the sidewall images. The gravel and sand are qualitatively divided into the coarsest layer, the coarse layer, the medium-coarse layer, and the fine layer through the particle size distribution. The specific method is that among all the particle size distribution curves, the particle size distribution curve that deviates from the overall particle size distribution curve and has a generally larger particle size is the coarsest layer (it can be not divided if there is none). After removing the coarsest layer, the content of particles smaller than a certain particle size is controlled according to about 1 / 3 ratio for each: near the average value is the "medium-coarse layer", below the upper envelope line is relatively the "fine layer", and above the lower envelope line is relatively the "coarse layer".

[0047] S4. Conduct engineering property tests on each geological area to obtain the engineering property parameters of the gravel and sand in each geological area.

[0048] Among them, the engineering property tests include: relative density test, consolidation test for coarse-grained soil, shear strength test for coarse-grained soil (direct shear test and triaxial shear test), linear stress-strain test, and permeability and permeability deformation test.

[0049] In the present invention, full-section sampling is carried out on multiple sampling structures in the material yard area for screening tests, and then the homogeneity index of the material yard area is determined according to the test results. When the homogeneity index meets the preset conditions, the material yard area is partitioned according to the test results, and finally the engineering properties of each layer of gravel and sand materials are determined according to the partitioning situation. In this way, the true situation of the particle distribution in the material yard can be comprehensively reflected, the availability of the gravel and sand layer as a building material can be clarified, thus saving a large amount of investment and being beneficial to environmental protection.

[0050] The above are only several embodiments of the present application, and do not impose any form of limitation on the present application. Although the present application is disclosed above with preferred embodiments, it is not intended to limit the present application. Any person skilled in the art, without departing from the scope of the technical solution of the present application, makes some changes or modifications using the technical content disclosed above, which are all equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. A method for determining the engineering characteristic parameters of dam materials made of deep gravel and sand, characterized in that, The method includes: S1. During the excavation of multiple sampling structures in the material yard area, the excavated materials and the sidewall images of the sampling structures are collected according to the excavation runs, and a full-section screening test is carried out on the excavated materials of each run to obtain the particle size distribution curve of the excavated materials of each run; S2. Determine the homogeneity index of the material yard area according to the excavated materials and their particle size distribution curves of all runs and the sidewall images of all runs of excavation; S3. When the homogeneity index meets the preset conditions, partition the material yard area according to the particle size distribution curves of the excavated materials of all runs and the sidewall images of all runs of excavation to obtain multiple geological areas; S4. Conduct engineering property tests on each geological area to obtain the engineering property parameters of the gravel and sand in each geological area.

2. The method according to claim 1, characterized in that The homogeneity index includes the particle defect rate, the content of each particle size group in the same layer of particles, the relative coarseness degree of particles in a single sampling structure, and the morphological characteristics of the particle size distribution curve.

3. The method according to claim 2, characterized in that The specific content of S2 includes: Determine the particle defect rate according to the excavated materials of each run and the sidewall images of each run of excavation, determine the content of each particle size group in the same layer of particles according to the particle size distribution curves of the excavated materials collected from multiple sampling structures at the same excavation height, determine the relative coarseness degree of particles in a single sampling structure according to the excavated materials collected from a single sampling structure at different excavation heights, and determine the morphological characteristics of the particle size distribution curve according to the particle size distribution curves of the excavated materials of all runs.

4. The method according to claim 2, wherein The specific content of S3 includes: When the particle defect rate, the content of each particle size group in the same layer of particles, the relative coarseness degree of particles in a single sampling structure, and the morphological characteristics of the particle size distribution curve are all good, partition the material yard area according to the particle size distribution curves of the excavated materials of all runs and the sidewall images of all runs of excavation to obtain multiple geological areas.

5. The method according to claim 1 or 4, characterized in that, In S3, partitioning the material yard area according to the particle size distribution curves of the excavated materials of all runs and the sidewall images of all runs of excavation to obtain multiple geological areas specifically includes: Determine the particle size stratification of the excavated materials of all runs according to the particle size distribution curves of the excavated materials of all runs, and determine the cementation situation and the situation of bad interlayers of all sampling structures according to the sidewall images of all runs of excavation; Partition the material yard area according to the particle size stratification situation, the cementation situation and the situation of bad interlayers to obtain multiple geological areas.

6. The method according to claim 5, wherein The determination of the particle size stratification of the excavated materials of all runs according to the particle size distribution curves of the excavated materials of all runs is specifically: Divide the particle sizes of the excavated materials of all runs into the coarsest layer, the coarse layer, the medium-coarse layer and the fine layer according to the particle size distribution curves of the excavated materials of all runs.

7. The method according to claim 1, characterized in that, The sampling structure includes multiple vertical shafts.

8. The method according to claim 7, characterized in that, The sampling structure also includes a chute arranged on the bank or the side of the ditch in the material yard area, running through the material layer from top to bottom.

9. The method according to claim 8, wherein The excavation footage of the chute and the vertical shaft is the same.

10. The method according to claim 1, wherein The engineering property tests include: relative density test, consolidation test of coarse-grained soil, shear strength test of coarse-grained soil, linear stress-strain test, and permeability and permeability deformation test.

Images