阅读说明：本技术 一种基于大样法的松散沉积层密度的测量方法 (Bulk deposition layer density measuring method based on bulk sample method ) 是由 耿涛 冯凡 杜辉 冯治汉 郭培虹 于 2020-06-19 设计创作，主要内容包括：本发明涉及一种基于大样法的松散沉积层密度的测量方法,包括：获取待研究的工作区不同类型松散沉积层的基本信息和分布区域及范围；根据不同类型松散沉积层的分布区域及范围大小,选择每种松散沉积层的采样数量及每个采样点的位置；根据每个采样点的位置信息,进行野外采样工作,获取六面体的采样坑及坑内所有物质；基于采样坑的六面体,测量六面体采样坑中用于进行体积计算时使用的边长信息、采样后得到的所有物质的重量；根据采样坑的边长信息及得到的所有物质的重量,基于预设公式,计算出该采样点处松散沉积层的密度。该方法不需对采样坑的几何形状作严格要求,避免了因采样坑体积计算不准确而引起的误差,使得测量的密度结果更真实和精确。(The invention relates to a loose sedimentary deposit density measuring method based on a bulk sample method, which comprises the following steps: acquiring basic information, distribution areas and ranges of different types of loose sedimentary layers in a working area to be researched; selecting the sampling quantity of each loose deposition layer and the position of each sampling point according to the distribution area and the range size of different types of loose deposition layers; according to the position information of each sampling point, carrying out field sampling work to obtain hexahedral sampling pits and all substances in the pits; measuring side length information used for volume calculation and the weight of all substances obtained after sampling in the hexahedron sampling pit based on the hexahedron of the sampling pit; and calculating the density of the loose settled layer at the sampling point based on a preset formula according to the side length information of the sampling pit and the obtained weights of all the substances. The method does not need to make strict requirements on the geometric shape of the sampling pit, avoids errors caused by inaccurate volume calculation of the sampling pit, and enables the measured density result to be more real and accurate.)

1. A loose sedimentary deposit density measuring method based on a bulk sample method is characterized by comprising the following steps:

101. acquiring basic information, distribution areas and range information of the distribution areas of different types of loose deposition layers in a working area to be researched;

102. selecting the sampling quantity of each loose deposition layer and the position of each sampling point according to the basic information, the distribution area and the range information of the distribution area of different types of loose deposition layers;

103. according to the position information of each sampling point, carrying out field sampling work to obtain a hexahedral sampling pit and all substances in the sampling pit;

104. measuring side length information used for volume calculation and the weight of all substances obtained after sampling in the hexahedron sampling pit based on the hexahedron of the sampling pit;

105. and calculating the density of the loose settled layer at the sampling point based on a preset formula according to the side length information of the sampling pit and the obtained weights of all the substances.

2. The method of claim 1, wherein the basic information of the loosely deposited layer includes the following: the times, types, and materials of loosely deposited layers.

3. The method of claim 1, wherein 103 comprises:

103-1, removing the sampling points and the surface loose layers of the extension areas of the sampling points at the selected sampling point positions until the relatively compact compacted layers are trimmed to be flat;

and 103-2, beginning to dig the sample, and obtaining the hexahedral sampling pit and all substances in the sampling pit.

4. The method of claim 3, wherein 103-2 comprises:

in the excavation process, if the loosely deposited layer of the sampling point collapses or is difficult to excavate due to other reasons, sampling is abandoned, a proper position is selected nearby, and the step 103-1 is executed again as a substitute for sampling failure.

5. The method of claim 3, wherein 103 further comprises:

five surfaces in the sampling pit are trimmed into a plane, each edge is trimmed into a straight line, the sampling pit is a hexahedron, and all substances dug out in sampling are recovered and weighed.

6. The method of claim 1, wherein 104 comprises:

and measuring the side length parameter to be measured of the sampling pit by adopting a metal folding ruler, measuring the position where two sides are intersected when arcs exist among all surfaces in the sampling pit, and determining each side length by adopting a repeated measurement and averaging value.

7. The method of claim 6, wherein the side length information comprises:

four side lengths and four downward side lengths at the opening of the sampling pit, the diagonal lengths of the opening surface and four side walls of the sampling pit and the four spatial diagonal lengths of the sampling pit.

8. The method of any of claims 1 to 7, wherein 105 comprises:

according to formula (1)Calculating the density of the loose deposition layer;

wherein: sigma is the sum of the weights of all the substances obtained after sampling, V_HexahedronThe volume of the sampling substance is obtained based on the side length information in the hexahedral sampling pit;

V_ithe volume of one tetrahedron after the hexahedron is divided into 6 tetrahedrons is represented, and the calculation formula is as follows: six edges of the tetrahedron O-ABC have BC ═ l, AB ═ n, AC ═ m, OA ═ p, OB ═ q, OC ═ r, respectively, then:

Technical Field

The invention relates to a loose sedimentary deposit density measuring method based on a bulk sample method.

Background

The gravity exploration is a geophysical exploration method which is used for finding out underground geological structures and finding energy sources for useful mineral resources by observing and researching the change rule of a natural gravity field on the basis of the density difference between different rocks (ores) in the crust. With the progress of the technology, the precision of the gravity survey technology is higher and higher, the application field is wider and wider, and correspondingly, the precision requirement on the known conditions is higher and higher.

In the gravity exploration work, a great deal of work is needed to measure the density of various strata and rocks (ores) exposed in a working area to serve as a known condition, and a foundation is laid for subsequent research work. The method is used for accurately measuring the density value of the loose sedimentary deposit, is an important component of density measurement work, has very important significance on correction, processing, inversion, explanation and research and the like of gravity data, and directly influences the accuracy and correctness of a final exploration result if the density values of various stratums and rocks (ores) are measured accurately. Thus, the specification requires that the mean square error of densitometry be better than. + -. 0.02g/cm³。

When the density of compact rock (ore) is measured, firstly, a certain amount of samples are respectively collected in the field according to the types of the rock (ore), the samples are measured by a method which is favorable for weighing by a balance and measuring the volume by measuring cylinder drainage indoors, then, the samples are classified for statistical analysis, and the density of the samples can be directly measured by various density measuring instruments at present. The structure of the compact rock (ore) specimen cannot be changed, so that measurement can be repeated, and measurement errors can be calculated. Different from the dense rock (ore) density measurement method, the structure of the loose sedimentary deposit is changed after excavation, so that the density value can be calculated only by measuring the volume of the sampling pit, and the density of the loose sedimentary deposit can be measured only in situ.

In various gravity specification regulations, no specific practice is given for the bulk sample method, but a certain volume of a loose sedimentary deposit sample is directly taken out according to a regular shape, the weight is measured, and the density is calculated by using the following formula.

Wherein: p is the weight of the bulk sample and V is the volume of the bulk sample.

Meanwhile, the specification suggests: when the bulk sedimentary deposit density is measured by a bulk sampling method, the sampling volume is moderate, and is preferably 0.5m multiplied by 0.5 m.

The density of the loose settled layer is measured by the large sample method in the field work at present. The method comprises the following steps:

in field work, a cuboid digging method is adopted when a large sample is dug, namely, a surface loose layer is peeled and flattened at a sampling point, then a standard cuboid (as shown in figure 1) with the square of about 0.5m multiplied by 0.5m is dug, the dug substances are respectively weighed while digging, after digging, the length (L), the width (W) and the depth (H) of the cuboid are measured, and the density of the loose deposition layer is directly calculated by the following formula.

Wherein: Σ P is the sum of the weights of all excavated materials in the cuboid.

The sampling method for the large sample is quite simple and convenient, and the result can be obtained through simple calculation on site, so the method is a method for measuring the density of a loose sedimentary layer which is generally adopted in the field work of gravity.

However, this method has a significant problem in that strict requirements are imposed on the shape of the sampling pit, and the shape must be a standard rectangular parallelepiped. However, in field work, especially in arid northwest areas, the loose sediment layer has low water content, high sand content and loose structure, so that the sample is usually trimmed and collapsed in the process of digging a large sample, and finally, a long time is taken, and the dug sampling pit is usually an irregular hexahedron similar to a cuboid, as shown in fig. 2.

The irregular hexahedron is generally large at the top and small at the bottom, so that the volume (V) calculated by calculating the length and width measured at the opening_Computing) Volume (V) of irregular hexahedron sampling pit than actual digging_{Practice of}) Is large, resulting in a final calculated bulk deposition density that is less than its actual density.

Through a large number of practical field investigations, it was found that the sampling pit, even if carefully trimmed, hardly reached the standard cuboid morphology, using the calculated volume (V)_Computing) And the actual volume of the sample well (V)_{Practice of}) Calculating density values respectively, and finding that the error is often smaller than 0.1-0.2 g/cm³And in some cases even larger, this is typically between 1.6 and 2.2g/cm³The relative error of the density values of the loose deposition layers is generally larger than 7-10% and even larger, which cannot be tolerated.

It should be noted that the error is the result obtained under the very serious working condition when the problem is researched, and in the general productive field gravity exploration work, because the large sample method is very simple, the work is basically not done as technical work but is completed as simple physical labor, so the actual error is often larger, and the large sample method has the characteristic of unrepeatable measurement, lacks quality inspection, and what is measured. This is also a significant reason why it is often seen in actual loose deposit density measurements that some density values are significantly smaller than the normal range, or even that extremely unreasonable data is present.

Therefore, how to obtain the accurate density of the loose deposition layer based on the bulk method becomes a problem that must be solved.

Disclosure of Invention

Technical problem to be solved

In order to solve the problems in the prior art, the invention provides a method for measuring the density of a loose deposition layer based on a large sample method, which does not need to make strict requirements on the geometric shape of a sampling pit, avoids errors caused by inaccurate volume calculation of the sampling pit, enables the measured density result to be more real and accurate, and can improve the field working efficiency and reduce the working strength.

(II) technical scheme

In order to achieve the purpose, the invention adopts the main technical scheme that:

the embodiment of the invention provides a loose sedimentary deposit density measuring method based on a bulk sample method, which comprises the following steps:

101. acquiring basic information, distribution areas and range information of the distribution areas of different types of loose deposition layers in a working area to be researched;

102. selecting the sampling quantity of each loose deposition layer and the position of each sampling point according to the basic information, the distribution area and the range information of the distribution area of different types of loose deposition layers;

103. according to the position information of each sampling point, carrying out field sampling work to obtain hexahedral sampling pits and all substances in the pits;

104. measuring side length information used for volume calculation and the weight of all substances obtained after sampling in the hexahedron sampling pit based on the hexahedron of the sampling pit;

105. and calculating the density of the loose settled layer at the sampling point based on a preset formula according to the side length information of the sampling pit and the obtained weights of all the substances.

Optionally, the basic information of the loosely deposited layer includes the following: the times, types, and materials of loosely deposited layers.

Optionally, 103 comprises:

103-1, removing the sampling points and the surface loose layers of the extension areas of the sampling points at the selected sampling point positions until the relatively compact compacted layers are trimmed to be flat;

and 103-2, beginning to dig the sample, and obtaining the hexahedral sampling pit and all substances in the sampling pit.

Optionally, 103-2 comprises:

in the excavation process, if the loosely deposited layer of the sampling point collapses or is difficult to excavate due to other reasons, sampling is abandoned, a proper position is selected nearby, and the step 103-1 is executed again as a substitute for the sampling failure of the sampling point.

Optionally, 103 further comprises:

five surfaces in the sampling pit are trimmed into a plane, each edge is trimmed into a straight line, the sampling pit is a hexahedron, and all substances dug out in sampling are recovered and weighed.

Optionally, 104 comprises:

and measuring the side length parameter to be measured of the sampling pit by adopting a metal folding ruler, measuring the position where two sides are intersected when arcs exist among all surfaces in the sampling pit, and determining each side length by adopting a repeated measurement and averaging value.

Optionally, the side length information includes:

four side lengths and four downward side lengths at the opening of the sampling pit, the length of the opening surface of the sampling pit and the diagonal lines of the four side walls and the length of the four spatial diagonal lines of the sampling pit are adopted, and the length of each side and the length of the diagonal line of the bottom surface of the sampling pit do not need to be measured.

Optionally, 105 comprises:

according to formula (1)Calculating the density of the loose deposition layer;

wherein: sigma P is the sum of the weights of all the substances obtained after sampling, V_HexahedronThe volume of the sampling substance is obtained based on the side length information in the hexahedral sampling pit;

V_ithe volume of one tetrahedron after the hexahedron is divided into 6 tetrahedrons is represented, and the calculation formula is as follows: six edges of the tetrahedron O-ABC have BC ═ l, AB ═ n, AC ═ m, OA ═ p, OB ═ q, OC ═ r, respectively, then:

(III) advantageous effects

The invention has the beneficial effects that: the method provided by the embodiment of the invention is mainly used for gravity exploration in geophysical exploration, the method does not need to be limited by the shape of the sampling pit in sampling, and can be carried out as long as the sampling pit is a hexahedron (the shape is easiest to dig compared with other geometric shapes). Therefore, the shape of the sampling pit does not need to be considered at any time during excavation, the interferences such as collapse and the like caused by uneven stratum materials can be avoided, and each surface in the sampling pit does not need to be considered too much during trimming and only needs to be trimmed into a plane.

The number of sampling pit parameters needing to be measured in the field is greatly increased compared with the conventional method, but the time and the energy are much smaller than those of the sampling pit shape which is trimmed carefully, so that the time and the cost are saved.

Drawings

FIG. 1 is a schematic diagram of a prior art bulk deposition density measurement using a bulk sample method;

FIG. 2 is a schematic diagram of the difference between actual sampling pits and theoretical sampling pits;

FIG. 3 is a schematic flow chart of a bulk deposition density measurement method based on a bulk sample method;

fig. 4(a) and 4(b) are schematic diagrams respectively illustrating the definition of hexahedron corner points, surface numbers and characteristic parameters;

FIGS. 4(c) and 4(d) are schematic diagrams of a form of a shape degradation of the hexahedral cell;

FIG. 5 is a schematic diagram of a coordinate system for calculating tetrahedral volumes;

FIG. 6 is a diagram illustrating measurement information in a method according to an embodiment of the invention;

FIG. 7 is a schematic diagram of a large sample density calculation program interface in the method of the present invention;

FIG. 8 is a schematic diagram of measuring side length in a method according to an embodiment of the present invention;

fig. 9 is a schematic diagram of a record table of measurement results in the method according to the embodiment of the present invention.

Detailed Description

For the purpose of better explaining the present invention and to facilitate understanding, the present invention will be described in detail by way of specific embodiments with reference to the accompanying drawings.

To better understand the scheme of the embodiment of the present application, a specific flow of the field density measurement work is first described, first: collecting data and performing field reconnaissance: the aim is to find out the distribution, type and range of various rocks and loose sedimentary formations. Secondly, the method comprises the following steps: designing a sampling route and a sampling point: the method aims to make a plan and ensure that each kind of rock and stratum are collected without omission. Generally, more than 30 compact rocks (ores) are required to be collected at different sampling points in an accumulated mode; the loose deposition layer is difficult to do so because of adopting a large sample method, and each type generally digs several to more than ten according to the distribution range, and the distribution is about one to dozens of square kilometers. Therefore, sampling at a nearby alternative point after sampling failure at one sampling point in the following embodiments can be regarded as same-point resampling. Thirdly, the method comprises the following steps: sampling and measuring: the compact rock (ore) is a collected sample, each block generally weighs 100-200 g, the compact rock (ore) is brought back indoors to measure the density by a densimeter, and a loose sedimentary deposit is measured on site by a bulk sample method. The scheme of the application is an improvement of the traditional bulk method. Fourthly: statistical analysis: even if the same rock or stratum is used, the material composition of the rock or stratum can be different due to different sampling positions, so that the measured density of each sample of the same rock or stratum can be changed within a small range, and therefore, the final density value of the rock or stratum needs to be determined through statistical analysis.

Different from the measurement of the density of compact rock (ore), the density of a loose settled layer is measured by a bulk sample method, which is not repeatable on the same sampling point, and the precision of the loose settled layer cannot be counted by repeated measurement. Therefore, each step in the sampling process is very important, and the accuracy of the final result is affected.

The method provided by the embodiment can avoid errors caused by inaccurate volume calculation of the sampling pit, accurately and efficiently obtain the density of the loose deposition layer in the working area to be researched, and ensure the accuracy of the result.