CN106644816B - An instrument and method for measuring saturated water content of soil - Google Patents

Abstract

The invention discloses an instrument and a method for measuring the saturated water content of soil. The instrument comprises two bases on which columns are installed vertically respectively. A crossbeam is arranged between the upright columns. A plurality of tension sensors are arranged on the crossbeam. The tension sensor The bottom is connected with nylon wires, and the tension sensor is connected with a wire cage through nylon wires. A ring knife is fixed inside the wire cage, and a container is placed outside the wire cage. The tension sensors are connected with wires, and the tension sensors are connected with an electronic control box through wires. The method includes the steps of measuring, soaking, calculating and the like. The invention has the advantage that it can accurately measure the time until the soil moisture content reaches saturation, without knowing the soil texture in advance, can accurately measure the water absorption and maximum water absorption of soil samples at different times, and accurately calculate the soil saturation moisture content .

Description

An instrument and method for measuring saturated water content of soil

technical field

The invention relates to the field of measuring soil saturated water content, in particular to an instrument and method for measuring soil saturated water content.

Background technique

In forest hydrological observation, the study of soil saturated moisture content is one of the very important contents. The existing method mainly adopts the ring knife soaking method with a fixed time length, according to the soil texture, the ring knife is weighed after soaking for several hours, and then the saturated water content of the soil is calculated. This method requires pre-determining the soil texture and then selecting the length of time. For soil, generally soak the ring knife for 8-12 hours. For soil with high clay content, you need to extend the soaking time of the ring knife; it is found in the study that the soaking time of the ring knife is too long or too short, which will affect the saturated water content of the soil. Determination accuracy; in addition, the time when soil water reaches saturation, as a variable that indirectly reflects soil texture, has not been taken seriously in forest hydrology research, and there is currently no method to study the time required for soil water to reach saturation.

Contents of the invention

The technical problem to be solved by the present invention is to provide an instrument and method for measuring soil saturated water content, which effectively solves the defects of the traditional ring-knife soaking method, and makes some improvements.

The technical problem to be solved by the present invention adopts the following technical solutions to realize:

A method for measuring soil saturated water content, using an instrument for measuring soil saturated water content, the instrument includes two bases, vertical columns are respectively installed on the bases, beams are arranged between the columns, and the A plurality of tension sensors are arranged on the crossbeam, and nylon wires are connected below the tension sensors, and the tension sensors are connected with wire cages through nylon wires, and the wire cages are used for fixing ring cutters, and the ring cutters are used for collecting soil , a container is placed outside the wire cage for containing water;

The tension sensors are all connected with wires, and the tension sensors are connected with an electronic control box through wires;

The electronic control box includes a battery and a paperless recorder, and the electronic control box is also provided with a switch;

The ring cutter is composed of a ring cutter body, a ring cutter top cover and a ring cutter bottom cover, and several circular holes are opened on the ring cutter top cover;

The processing method of the ring cutter comprises the following steps: first, drilling or punching is carried out on the top cover of the ring cutter to form a plurality of holes with a diameter of 1 mm; The joint of the knife body is wound twice to ensure that the ring knife is immersed in water from the position of the perforated ring knife cover during the soaking process;

The method for measuring soil saturated water content may further comprise the steps:

a. Adjust the length of the nylon wire between the wire cage and the tension sensor, so that the ring knife cover at one end of the ring blade can just submerge into the water;

b. Turn on the switch of the electronic control box, pre-set the time measurement step of the paperless recorder, put the wire cage still, and perform zero processing on the paperless recorder;

c. Put the ring knife in the wire cage, make sure that the edge of the ring knife is upward, the wire cage is used to fix the position of the ring knife, let it stand still, then gently put the wire cage into a container filled with water, and hang it in the water;

d. After soaking for a certain period of time, download the data in the paperless recorder, including: the weight m ₀ of the ring knife and the collected soil sample, the readings m ₁ of the tension and pressure sensor of the ring knife and the wire cage just placed in the container, The readings m _x of the tension and pressure sensors at different time points, and the m _max when the maximum reading is reached during the soaking process, and the corresponding times t ₀ , t ₁ , t _x , t _max for each reading;

e. After the end, remove the waterproof tape wrapped around the ring knife, open the ring knife cover, put the ring knife body and ring knife cover in an oven to dry at 105°C to constant weight, and dry the removed waterproof tape together with the Weigh the ring cutter body (including soil) and ring cutter cover m ₀₀ , wash the soil in the ring cutter body and dry it, then weigh the ring cutter body (excluding soil) and ring cutter cover m ₀₁ ;

f. Calculated according to the formula, natural water content = (m ₀ -m ₀₁ )/(m ₀₀ -m ₀₁ )×100%, saturated water content = (m _max -m ₁ +m ₀ -m ₀₁ )/( m ₀₀ -m ₀₁ )×100%.

The beneficial effects of the present invention are:

1) It can accurately determine the time when the soil moisture content reaches saturation, without knowing the soil texture in advance, it can accurately measure the water absorption and maximum water absorption of soil samples at different times, and accurately calculate the soil saturation moisture content;

2) The change process of moisture content of different soil samples during soaking time can be compared;

3) According to the number of channels of the paperless recorder, multiple sets of the above parameters can be measured at the same time.

Description of drawings

Fig. 1 is the structural representation of the instrument that the present invention introduces;

Fig. 2 is the schematic diagram of each component after ring cutter is disassembled;

Figure 3 is a schematic diagram of the ring knife assembly

Among them, 1-base, 2-column, 3-beam, 4-tension sensor, 5-nylon wire, 6-wire cage, 7-ring knife, 71-ring knife body, 72-ring knife bottom cover, 73-ring Knife top cover, 74-round hole, 75-waterproof tape, 8-container, 9-wire, 10-electronic control box.

Detailed ways

In order to make the technical means, creative features, goals and effects achieved by the present invention easy to understand, the present invention will be further described below in conjunction with specific illustrations.

As shown in Figure 1, an instrument for measuring the saturated water content of soil includes two bases 1, and the bases 1 are respectively vertically equipped with columns 2, and beams 3 are arranged between the columns 2, and several tension sensors are arranged on the beams 3 4. A nylon thread 5 is connected below the tension sensor 4, and the tension sensor 4 is connected to a wire cage 6 through the nylon thread 5. A ring knife 7 is fixed inside the wire cage 6 for collecting and storing soil. Outside the wire cage 6, a Container 8 is used to hold water;

Pull sensor 4 is connected with lead 9, and pull sensor 4 is connected with electronic control box 10 by lead 9, and electronic control box includes battery and paperless recorder (not shown in the figure), and described electronic control box is also provided with switch ( not shown in the figure). As shown in Figure 2, ring cutter 7 is made up of ring cutter body 71 and two ring cutter covers 72, and described two ring cutter covers 72 are positioned at the upper end and the lower end of ring cutter body 71 respectively, and described ring cutter cover 72 has Several round holes 73.

As shown in Figure 2 and Figure 3, the processing assembly of above-mentioned ring cutter 7 is ring cutter body 71, ring cutter top cover 73 and ring cutter bottom cover 72, at first carries out drilling or punching processing on ring cutter top cover 73, It is 1mm circular hole 74 to form some apertures; Then use waterproof adhesive tape 75 to wrap two circles at ring knife top cover 73, ring knife bottom cover 72 and ring knife body 71 joints, to ensure that ring knife 7 is all covered by perforated ring in soaking process. The position of the knife cover is soaked in water.

The above-mentioned instrument for determining soil saturated water content adopts the following steps during measurement, including:

a. Adjust the length of the nylon wire 5 between the wire cage 6 and the tension sensor 4, so that the ring knife cover at one end of the ring blade can just submerge into the water;

B, open electronic control box 10 switches, pre-set the time measurement step length of paperless recorder, wire cage 6 is left standstill, and carry out zeroing processing on paperless recorder;

c. Put the ring knife 7 in the wire cage 6, make sure that one end of the ring knife edge is upward, the wire cage 6 is used to fix the position of the ring knife 7, let it stand, and then gently put the wire cage 6 into the container 8 filled with water, and suspended in water;

d. After soaking for a certain period of time, download the data in the paperless recorder, including: the ring knife 7 and the weight m ₀ of the collected soil sample, the tension pressure sensor that the ring knife 7 and the wire cage 6 have just been placed in the container 8 4 readings m ₁ , 4 readings m _x of tension and pressure sensors at different time points, and m _max when the maximum reading is reached during soaking, and the time t ₀ , t ₁ , t _x , t _max corresponding to each reading;

e. After the end, remove the waterproof tape wrapped around the ring knife 7, open the ring knife cover, put the ring knife body and the ring knife cover in an oven to dry at 105°C to constant weight, and dry the removed waterproof tape together with the oven Weigh the dry ring cutter body (containing soil) and ring cutter cover m ₀₀ , wash the soil in the ring cutter body, and after drying, weigh the ring cutter body (excluding soil) and ring cutter cover m ₀₁ ;

f. Calculated according to the formula, natural water content = (m ₀ -m ₀₁ )/(m ₀₀ -m ₀₁ )×100%, saturated water content = (m _max -m ₁ +m ₀ -m ₀₁ )/( m ₀₀ -m ₀₁ )×100%.

The basic principles, main features and advantages of the present invention have been shown and described above. Those skilled in the industry should understand that the present invention is not limited by the above-mentioned embodiments. What are described in the above-mentioned embodiments and the description only illustrate the principle of the present invention. Without departing from the spirit and scope of the present invention, the present invention will also have Variations and improvements are possible, which fall within the scope of the claimed invention. The protection scope of the present invention is defined by the appended claims and their equivalents.

Claims (1)

1. a method for measuring soil saturated water content is characterized in that: utilize the instrument of measuring soil saturated water content to measure, and described instrument comprises two bases, and column is vertically installed respectively on the described base, and between described column A crossbeam is arranged between, and several tension sensors are arranged on the crossbeam, and nylon wires are connected under the tension sensors, and the tension sensors are connected with wire cages through nylon wires, and the wire cages are used for fixing ring knives. The ring knife is used to collect soil, and a container is placed outside the wire cage for containing water; The tension sensors are all connected with wires, and the tension sensors are connected with an electronic control box through wires; The electronic control box includes a battery and a paperless recorder, and the electronic control box is also provided with a switch; The ring cutter is composed of a ring cutter body, a ring cutter top cover and a ring cutter bottom cover, and several circular holes are opened on the ring cutter top cover; The processing method of the ring cutter comprises the following steps: first, drilling or punching is carried out on the top cover of the ring cutter to form a plurality of holes with a diameter of 1 mm; The joint of the knife body is wound twice to ensure that the ring knife is immersed in water from the position of the perforated ring knife cover during the soaking process; The method for measuring soil saturated water content may further comprise the steps: a. Adjust the length of the nylon wire between the wire cage and the tension sensor, so that the ring knife cover at one end of the ring blade can just submerge into the water; b. Turn on the switch of the electronic control box, pre-set the time measurement step of the paperless recorder, put the wire cage still, and perform zero processing on the paperless recorder; c. Put the ring knife in the wire cage, make sure that the edge of the ring knife is upward, the wire cage is used to fix the position of the ring knife, let it stand still, then gently put the wire cage into a container filled with water, and hang it in the water; d. After soaking for a certain period of time, download the data in the paperless recorder, including: the weight m ₀ of the ring knife and the collected soil sample, the readings m ₁ of the tension and pressure sensor of the ring knife and the wire cage just placed in the container, The readings m _x of the tension and pressure sensors at different time points, and the m _max when the maximum reading is reached during the soaking process, and the corresponding times t ₀ , t ₁ , t _x , t _max for each reading; e. After the end, remove the waterproof tape wrapped around the ring knife, open the ring knife cover, put the ring knife body and ring knife cover in an oven to dry at 105°C to constant weight, and dry the removed waterproof tape together with the Weigh the soil-containing ring cutter body and ring cutter cover m ₀₀ , wash the soil in the ring cutter body, and after drying, weigh the ring cutter body and ring cutter cover without soil m ₀₁ ; f. Calculated according to the formula, natural water content = (m ₀ -m ₀₁ )/(m ₀₀ -m ₀₁ )×100%, saturated water content = (m _max -m ₁ +m ₀ -m ₀₁ )/( m ₀₀ -m ₀₁ )×100%.

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