A method for evaluating the water stability of ecologically improved soil aggregates

Abstract

This invention discloses an evaluation method for the water stability of ecologically improved soil aggregates, comprising the following steps: (1) Soil aggregate immersion experiment, collecting mass data and critical state time consumption during the entire immersion process of aggregates; (2) Obtaining the water absorption rate V of aggregates based on the capillary water absorption time and mass data during the pre-immersion process of aggregates; (3) Obtaining the sieving particle size coefficient D based on the remaining mass on each layer of sieves after the aggregates have stabilized from immersion; (4) Obtaining the water stability coefficient S of aggregates by combining the three parameters of the remaining mass on the first layer of sieves, the water absorption rate of aggregates, and the sieving particle size coefficient, and evaluating the water stability of ecologically improved soil aggregates; This invention has a wide range of soil evaluation methods and a complete evaluation method, solving the problem that existing soil aggregate water stability evaluation methods have single parameters and cannot fully reflect the ecological improvement effect of soil aggregates.

Description

Technical Field

[0001] This invention relates to the field of soil and water conservation and soil improvement technology, specifically to a method for evaluating the water stability of ecologically improved soil aggregates. Background Technology

[0002] Improving soil aggregates with ecological materials can effectively enhance their water stability, thus providing a favorable substrate environment for vegetation growth. Improved aggregates exhibit characteristics such as prolonged disintegration time, large residual mass, and granular composition upon contact with water. Existing methods for evaluating the water stability of soil aggregates rely on single parameters, specifically the quantity or mass of disintegrated aggregates. They lack parameters that express the soil aggregates' resistance to water intrusion, such as water absorption rate and the distribution characteristics of disintegrated soil particles, thus failing to effectively and comprehensively evaluate the ecological improvement effects of soil aggregates. Summary of the Invention

[0003] To effectively and comprehensively evaluate the ecological improvement effects of soil aggregates and overcome the lack of parameters characterizing the water intrusion resistance of soil aggregates, a method for evaluating the water stability of ecologically improved soil aggregates has been invented. This invention has a wide range of soil types to evaluate and a comprehensive evaluation method, which can effectively guide soil and water conservation projects or soil ecological improvement projects.

[0004] I. The present invention proposes a method for evaluating the water stability of ecologically improved soil aggregates, comprising the following steps:

[0005] (1) Agglomerate immersion test

[0006] Record the initial mass m0 of the aggregate; pre-wet the aggregate to allow it to absorb water through capillary action, record the time t0 required for the aggregate to begin absorbing water and become fully wet, and record the mass m0' of the aggregate when it is fully wetted. The pre-wetting time is set to a maximum of one minute depending on the soil type of the aggregate being measured; allow the aggregate to disintegrate completely in water, and record the mass of the residue on the four sieves (m1, m2, m3, m4) after the aggregate has disintegrated and stabilized.

[0007] (2) Calculate the water absorption rate V of the aggregates.

[0008] Based on the capillary water absorption time and aggregate mass data during the pre-impregnation process of the aggregates, the water absorption rate V of the aggregates is characterized by the amount of water absorbed per unit time, and the calculation formula is: V=(m0'-m0) / t, with the dimension g / s.

[0009] (3) Calculate the sieve particle size coefficient D

[0010] The sieving particle size coefficient D is calculated from the cumulative residual mass percentage on each layer of the sieve, and has a dimension of 1. The calculation formula is as follows: D = (M L2 +ML3 +M L4 -3M L1 ) / (100-M L1 )

[0011] Among them: ①M Lx To accumulate the remaining mass percentage, M Lx =m Lx +m L(x-1) (x takes integers from 1 to 4);

[0012] ②m Lx m represents the percentage of remaining mass in each layer of the screen. Lx =m x / m0×100 (x takes integer values ​​from 1 to 4);

[0013] The larger the sieve particle size coefficient D, the larger the aggregates of the disintegrating soil, indicating that the ecological material has a better bonding effect and a stronger ability to maintain its integrity after being soaked in water.

[0014] (4) Calculate the water stability coefficient S and evaluate the water stability of soil aggregates.

[0015] The water stability coefficient S of the aggregates is calculated by considering three main parameters: the remaining mass m1 of the first-layer sieve, the water absorption rate V of the aggregates, and the sieve particle size coefficient D, to evaluate the water stability of the ecologically improved soil aggregates. The water stability coefficient S is directly proportional to the remaining mass m1 of the first-layer sieve and the sieve particle size coefficient D, and inversely proportional to the water absorption rate V of the aggregates. Its dimension is s, and the calculation formula is as follows:

[0016] S=D·m1 / V

[0017] The larger the water stability coefficient S, the better the water stability of the aggregates, indicating that the aggregates remain stable for a longer period of time after encountering water.

[0018] II. The significant advantages of this invention are:

[0019] (1) Based on the remaining mass of aggregates after sieving, the parameters characterizing the particle size of aggregates are obtained by formula calculation method, which solves the problem that the particle size of disintegrated soil is difficult to measure accurately.

[0020] (2) The evaluation parameters are comprehensive and can truly reflect the ecological improvement effect of soil aggregates. Detailed Implementation

[0021] The specific embodiments of the present invention will be described in further detail below with reference to examples.

[0022] Example 1:

[0023] This invention proposes a method for evaluating the water stability of ecologically improved soil aggregates, comprising the following steps:

[0024] (1) Agglomerate immersion test

[0025] The sample was a clay aggregate modified with 5% organic binder, with an initial mass of 50g. The aggregate was pre-wetted to allow it to absorb water through capillary action. The time from the start of water absorption to complete wetting was 38s, and the mass of the fully wetted aggregate was 60g. The aggregate was then allowed to disintegrate completely in water. The time for the aggregate to stabilize after disintegration was recorded as 90s. The mass of residue on the four sieves was 20g, 10g, 15g, and 0g, respectively.

[0026] (2) Calculate the water absorption rate V of the aggregates.

[0027] The capillary water absorption of soil aggregates during the pre-infiltration process is calculated as m0'-m0=60g-50g=10g; substituting the capillary water absorption time of 38s into the formula for calculating the water absorption rate V of the aggregates, the result is: V=(m0'-m0) / t0=10 / 38=0.263g / s.

[0028] (3) Calculate the sieve particle size coefficient D

[0029] ① Calculate the percentage of remaining mass in each layer of the screen, which is m L1 =m1 / m0 = 20 / 50 × 100 = 40;

[0030] m L2 =m2 / m0 = 10 / 50 × 100 = 20;

[0031] m L3 =m3 / m0 = 15 / 50 × 100 = 30;

[0032] m L4 =m4 / m0 = 0 / 50 × 100 = 0;

[0033] ② Calculate the cumulative remaining mass percentage, respectively

[0034] M L1 =m L1 =40;

[0035] M L2 =m L2 +m L1 =20 + 40 = 60;

[0036] M L3 =m L3 +m L2 =30 + 60 = 90;

[0037] M L4 =m L4 +m L3 =0 + 90 = 90;

[0038] ③ Calculate the sieve particle size coefficient DD = (M L2 +M L3 +M L4 -3M L1 ) / (100-M L1 )=(60+90+90-3×40) / (100-40)=2.

[0039] (4) Calculate the water stability coefficient S

[0040] Substituting the remaining mass of the first layer of screen (20g), the water absorption rate of the agglomerates (0.263), and the sieve particle size coefficient (2) into the formula for calculating the water stability coefficient S, we get: S = D·m1 / V = 2 × 20 / 0.263 ≈ 152s.

[0041] Example 2:

[0042] This invention proposes a method for evaluating the water stability of ecologically improved soil aggregates, comprising the following steps:

[0043] (1) Agglomerate immersion test

[0044] The sample was a clay aggregate modified with 0.5% organic binder, with an initial mass of 50g. The aggregate was pre-wetted to allow it to absorb water through capillary action. The time from the start of water absorption to complete wetting was 10s, and the mass of the fully wetted aggregate was 76g. The aggregate was then allowed to disintegrate completely in water. The time for the aggregate to stabilize after disintegration was recorded as 60s. The mass of the residue on the four sieves was 10g, 6g, 10g, and 15g, respectively.

[0045] (2) Calculate the water absorption rate V of the aggregates.

[0046] The capillary water absorption of soil aggregates during the pre-infiltration process is calculated as m0'-m0=76g-50g=26g; substituting the capillary water absorption time of 10s into the formula for calculating the water absorption rate V of the aggregates, the result is: V=(m0'-m0) / t0=26g / 10s=2.6g / s.

[0047] (3) Calculate the sieve particle size coefficient D

[0048] ① Calculate the percentage of remaining mass in each layer of the screen, which is m L1 =m1 / m0 = 10 / 50 × 100 = 20;

[0049] m L2 =m2 / m0 = 6 / 50 × 100 = 12;

[0050] m L3 =m3 / m0 = 10 / 50 × 100 = 20;

[0051] mL4 =m4 / m0 = 15 / 50 × 100 = 30;

[0052] ② Calculate the cumulative remaining mass percentage, respectively

[0053] M L1 =m L1 =20;

[0054] M L2 =m L2 +m L1 =12+20=32;

[0055] M L3 =m L3 +m L2 =20 + 32 = 52;

[0056] M L4 =m L4 +m L3 =30 + 52 = 82;

[0057] ③ Calculate the sieve particle size coefficient DD = (M L2 +M L3 +M L4 -3M L1 ) / (100-M L1 = (32+52+82-3×20) / (100-20) = 1.325.

[0058] (4) Calculate the water stability coefficient S

[0059] Substituting the remaining mass of the first layer of screen (10g), the water absorption rate of the agglomerates (2.6), and the sieve particle size coefficient (1.325) into the formula for calculating the water stability coefficient S, we get: S = D·m1 / V = 1.325 × 10 / 2.6 ≈ 5.1s.

[0060] In summary, comparing the water stability of clay aggregates modified with 0.5% and 5% organic binders, it was found that the clay aggregates modified with 5% organic binder had better water stability, and the aggregates remained stable for a longer time after contact with water, approximately 30 times longer than those modified with 0.5% organic binder. The aggregates also had a stronger ability to maintain their integrity in water, approximately 1.5 times that of those modified with 0.5% organic binder.

Claims

1. A method for evaluating the water stability of an ecological improved soil aggregate, characterized by It comprises the following steps: (1) soil aggregate immersion experiment, the mass data and critical state time consumption in the whole process of aggregate immersion are collected, including: recording the initial mass m0 of the aggregate; pre-soaking the aggregate, recording the time t0 required for the aggregate to start absorbing water through capillary action to full wetting, recording the mass m0' of the aggregate when fully wet; making the aggregate fully immersed in water to disintegrate, recording the remaining mass m1, m2, m3, m4 on the four-layer screen after the aggregate disintegrates stably; (2) according to the capillary water absorption time t0 and mass data m0' and m0 in the pre-soaking process of the aggregate, the water absorption rate V of the aggregate is obtained; (3) according to the remaining mass m1, m2, m3, m4 on each layer of screen after the aggregate is immersed stably, the screen particle size coefficient D is obtained, the screen particle size coefficient D is calculated by the cumulative residual mass percentage M on the four-layer screen, the calculation formula is: D=(M L2 +M L3 +M L4 -3M L1 ) / (100-M L1 ), the dimension is 1, wherein: ①M Lx is the cumulative residual mass percentage, M Lx =m Lx +m L(x-1) , x is an integer from 1 to 4; ②m Lx is the residual mass percentage of each layer of screen, m Lx =m x / m0x100, x is an integer from 1 to 4, the larger the screen particle size coefficient D, the larger the aggregate of the disintegrated soil, indicating that the binding effect of the ecological material is better, and the ability to maintain the integrity of the aggregate after immersion is stronger; (4) combining the three parameters of the residual mass m1 of the first layer of screen, the water absorption rate V of the aggregate and the screen particle size coefficient D, the water stability coefficient S of the aggregate is obtained, the water stability of the ecological improved soil aggregate is evaluated, the water stability coefficient S is proportional to the residual mass m1 of the first layer of screen and the screen particle size coefficient D, and is inversely proportional to the water absorption rate V of the aggregate, the calculation formula is: S=D·m1 / V, the dimension is s, the larger the water stability coefficient S, the better the water stability of the aggregate, indicating that the stable time of the aggregate after water is longer.

2. The method for evaluating the water stability of an ecological improved soil aggregate according to claim 1, characterized in that: The pre-infiltration process of the aggregate absorbs water by capillary action for a time t0, which is determined by the type of the aggregate soil, and is set to be one minute at the longest.

3. The method for evaluating the water stability of an ecological improved soil aggregate according to claim 1, characterized in that: The water absorption rate V of the aggregate is represented by the amount of water absorbed by the aggregate per unit time, and is calculated by the formula: V=(m0'-m0) / t0, with the dimension of g / s.