CN112964553A - Cement soil uniaxial tension tester and testing method - Google Patents
Cement soil uniaxial tension tester and testing method Download PDFInfo
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- CN112964553A CN112964553A CN202110167961.1A CN202110167961A CN112964553A CN 112964553 A CN112964553 A CN 112964553A CN 202110167961 A CN202110167961 A CN 202110167961A CN 112964553 A CN112964553 A CN 112964553A
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- 239000002689 soil Substances 0.000 title claims abstract description 104
- 239000004568 cement Substances 0.000 title claims abstract description 92
- 238000012360 testing method Methods 0.000 title claims abstract description 54
- 238000011068 loading method Methods 0.000 claims abstract description 39
- 238000006073 displacement reaction Methods 0.000 claims abstract description 26
- 238000010998 test method Methods 0.000 claims abstract description 8
- 230000008859 change Effects 0.000 claims abstract description 7
- 238000003825 pressing Methods 0.000 claims description 45
- 238000000034 method Methods 0.000 claims description 20
- 230000005540 biological transmission Effects 0.000 claims description 17
- 238000009864 tensile test Methods 0.000 claims description 7
- NIXOWILDQLNWCW-UHFFFAOYSA-N acrylic acid group Chemical group C(C=C)(=O)O NIXOWILDQLNWCW-UHFFFAOYSA-N 0.000 claims description 3
- 238000009499 grossing Methods 0.000 claims description 2
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- 238000009826 distribution Methods 0.000 description 5
- 238000004088 simulation Methods 0.000 description 4
- 238000010586 diagram Methods 0.000 description 3
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- 230000001276 controlling effect Effects 0.000 description 2
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- 239000000835 fiber Substances 0.000 description 2
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- 238000004026 adhesive bonding Methods 0.000 description 1
- 238000004873 anchoring Methods 0.000 description 1
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N3/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N3/08—Investigating strength properties of solid materials by application of mechanical stress by applying steady tensile or compressive forces
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N2203/0001—Type of application of the stress
- G01N2203/0012—Constant speed test
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N2203/0014—Type of force applied
- G01N2203/0016—Tensile or compressive
- G01N2203/0017—Tensile
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N2203/02—Details not specific for a particular testing method
- G01N2203/025—Geometry of the test
- G01N2203/0252—Monoaxial, i.e. the forces being applied along a single axis of the specimen
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N2203/02—Details not specific for a particular testing method
- G01N2203/06—Indicating or recording means; Sensing means
- G01N2203/067—Parameter measured for estimating the property
- G01N2203/0676—Force, weight, load, energy, speed or acceleration
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N2203/02—Details not specific for a particular testing method
- G01N2203/06—Indicating or recording means; Sensing means
- G01N2203/067—Parameter measured for estimating the property
- G01N2203/0682—Spatial dimension, e.g. length, area, angle
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Abstract
The invention relates to a cement soil uniaxial tension tester and a test method, belonging to the field of cement soil sample test equipment. A power loading system, a measuring system and a sample positioning and stretching system are arranged on a test main body platform of the tester; the sample positioning and stretching system is used for placing the detected cement soil sample; the dynamic loading system drives the sample positioning and stretching system, and the measuring system is used for acquiring the tension and displacement change data of the sample positioning and stretching system. The loading mode of the cement soil uniaxial tensile tester is strain control, compared with the traditional uniaxial tensile tester, the cement soil uniaxial tensile tester can measure a complete cement soil tensile stress-strain relation curve and analyze the influence of the loading rate on the tensile property of cement soil, so that the loading rate with the minimum influence on the test of the tensile strength of a cement soil sample is selected by comparison.
Description
Technical Field
The invention relates to a cement soil uniaxial tension tester and a test method, belonging to the field of cement soil sample test equipment.
Background
The tensile strength of cement soil is not utilized in engineering construction, but the phenomenon of tensile fracture and damage of a cement soil structure is not rare under certain specific working conditions. For example, cement soil structures around high-voltage power transmission line towers and other large buildings are often cracked due to insufficient tensile strength, cement soil mixing piles are often subjected to eccentric compression to cause tensile stress on partial structures, and when pile bodies are subjected to large bending deformation, the problems of cracking, damage and the like are caused. In recent years, the problems of improving the tensile property of cement soil and how to accurately measure the tensile strength of cement soil are valued by a plurality of geological and geotechnical engineering experts and scholars at home and abroad.
At present, in some domestic and foreign documents, the tensile strength of cemented soil is mostly determined by a method for testing the tensile strength of cohesive soil. These methods are classified into two categories: indirect assays and direct assays. The indirect measurement method is mainly characterized in that the tensile failure of cement soil is supposed to accord with a certain stress-strain relation, the value of the compressive stress is calculated and converted into the tensile strength of a sample through certain specific theoretical formulas, and the common test methods comprise a soil beam bending method, a radial fracturing method, an axial fracturing method, an air pressure fracturing method and the like. Because indirect measurement methods have more theoretical assumptions, the tensile strength obtained by formula conversion is greatly different from the actual situation, and the tensile strength of the cement soil measured by different test methods is different, most of the tensile strength cannot truly and accurately reflect the cement soil tensile failure process. The direct measurement method is to apply axial tensile load to make the sample fail in the stretching process, and comprises a uniaxial stretching method and a triaxial stretching method, and the uniaxial stretching method is common, and the method is an ideal way for researching the tensile property of the cement soil and disclosing the tension fracture mechanism of the cement soil. However, how to fix the two ends of the sample is a technical problem which is difficult to overcome, and the fixing modes commonly adopted at present generally comprise a sticking type, an external clamp anchoring type and a wedge-shaped clamp. But the front end face of the sticking type sticking needs polishing and gluing, the treatment process is complex, and the sticking type sticking is easy to fail; the clamp head of outer clamp anchor type can produce restraint stress in the place of test piece restraint, easily causes the test piece impaired even fracture, and the clamp head easily forms eccentric load when not inseparable with the test piece combination in addition, produces great error to the test result. The existing some specially-made wedge-shaped clamps, such as 8-shaped moulds, have the defects that the section change rate of a test piece is large, large stress concentration damage is easily generated at the position of a variable section, in addition, some moulds with complex plane section shapes exist, the test sample preparation operation is complicated, and the test piece is easily damaged in the demoulding process.
In addition, the patent application number of the invention is as follows: 202010716525.0, title of the invention: compared with the test method of the integral soil uniaxial tension device, the middle part of the soil uniaxial tension device is provided with a cuboid transition section, the position of the fracture surface of the sample is positioned in the cuboid transition section in the stretching process, but the position and the number of the fracture surfaces are uncertain, the fracture points on two sides are probably asymmetric, furthermore, the area of the cross section is difficult to determine, but the cement soil uniaxial tension tester adopts a variable cross section symmetrical structure mould with big ends and small middle parts to tension the sample, the position of the fracture surface of the sample is unique, the area of the cross section is fixed, the connection point of the sample at the position with the minimum area of the cross section in the middle of the mould is uniformly fractured, the cement soil uniaxial tensile tester is not only suitable for measuring pure soil with lower tensile strength, but also suitable for cement solidified soil and fiber reinforced soil with higher tensile strength, and has wider applicability.
The existing uniaxial tensile test device mainly adopts a stress control mode, namely, loading control is performed by gradually adding weights, and one remarkable defect is that a complete cement soil tensile stress-strain relation curve cannot be measured, and the brittle failure phenomenon can occur when a sample reaches ultimate tensile strength.
Disclosure of Invention
The invention aims at the problems that the operation is complicated and the section position of the sample is not easy to control in the prior art; the sample is difficult to fix in the process of the tensile test, and eccentric load is easy to form; the test piece is easy to damage or break at the constraint part of the clamping head; due to sudden change of the section of the test piece, a part of the die is easy to generate larger stress concentration damage at the variable section, so that the reliability of the test result is reduced; the stress control type loading method can not measure the complete tensile stress-strain curve of the cement soil sample, the loading process is easily influenced by human factors, the precision of the test result can not be ensured, and the like, and provides the cement soil uniaxial tensile tester and the test method.
The invention adopts the following technical scheme:
the invention relates to a cement soil uniaxial tensile tester which comprises a test main body platform, a dynamic loading system, a measuring system and a sample positioning tensile system; a power loading system, a measuring system and a sample positioning and stretching system are arranged on the test main body platform; the sample positioning and stretching system is used for placing the detected cement soil sample; the dynamic loading system drives the sample positioning and stretching system, and the measuring system is used for acquiring the tension and displacement change data of the sample positioning and stretching system.
The invention relates to a cement soil uniaxial tensile tester.A power loading system comprises a motor, a power transmission shaft and a control box; the motor is controlled by the control box, and a driving end of the motor is provided with a power transmission shaft.
The invention relates to a cement soil uniaxial tension tester.A measuring system comprises a first connecting rod, a displacement sensor, a tension sensor, a data collector and a connecting bolt; the measuring system is connected with the power loading system through a first connecting rod, the displacement sensor is arranged on the test main body platform, a baffle is fixed on the first connecting rod, the baffle is in contact with the displacement sensor, and the acquisition end of the data acquisition unit is respectively connected with the displacement sensor and the tension sensor.
According to the cement-soil uniaxial tensile tester, a power transmission shaft in a power loading system is connected with a connecting rod I in a measuring system through a tension sensor.
The invention relates to a cement soil uniaxial tensile tester.A sample positioning and tensile system comprises a guide sliding die end, a fixed die end, a sliding platform plate, a fixed platform plate, a pulley and a rail base plate; the rail backing plate is fixed on the test main body platform through a fixing bolt, and a guide sliding die end and a fixed die end are arranged on the rail backing plate; the guide sliding mold end and the fixed mold end are spliced in a non-fixed mode; placing a cement soil sample in a space enclosed by splicing the guide sliding mold end and the fixed mold end;
a pulley for guiding is arranged between the guiding sliding die end and the rail backing plate, and the fixed die end and the rail backing plate are fixed with each other through a fixing bolt;
the die cavities in the guide sliding die end and the fixed die end are trapezoidal die cavities, and the furled ends of the trapezoidal die cavities in the guide sliding die end and the fixed die end are mutually spliced.
According to the cement-soil uniaxial tensile tester, the tail end of the track base plate, which is positioned at the end of the fixed mould, is vertically provided with the fixed baffle, and a second connecting rod is arranged between the fixed baffle and the end of the fixed mould.
According to the cement soil uniaxial tensile tester, a cement soil sample is prepared through a sample pressing mold and a sample pressing piston; the inner cavity of the sample pressing mold is of a variable cross-section symmetrical structure with two large ends and a small middle part; the sample pressing mold is provided with a piston hole, and the size of the piston hole is matched with that of the sample pressing piston.
The invention relates to a cement soil uniaxial tensile tester, wherein a sample pressing piston is provided with a positioning hole, and a positioning pin is arranged in the positioning hole of the sample pressing piston.
The testing method of the cement soil uniaxial tension tester comprises the following steps:
step one, preparing a sample: placing a sample pressing mold in a tray with an acrylic plate at the bottom, then loading the mixed cement soil into the mold for three times and placing a sample pressing piston, placing the tray on a vibrating table after the first two sample loading, vibrating for two minutes and scratching the surface, and finally loading the cement soil into the mold to a required height and smoothing the surface;
step two, loading a sample: pushing the cured cement soil sample out of the sample pressing mold by using a sample pressing piston, and placing the sample in a space enclosed by a guide sliding mold end and a fixed mold end;
step three, setting a test tensile value and executing a test: clearing the values of a displacement sensor and a tension sensor, setting a tensile displacement rate through a control box, performing a uniform-speed tensile test through a power transmission shaft, and acquiring tensile stress and displacement data through a data acquisition unit until a cement soil sample is completely broken;
and step four, repeating the step three to carry out tests aiming at different tests until all the test samples are tested.
According to the testing method of the cement soil uniaxial tension tester, in the first step, the height of the prepared sample is controlled by using the positioning pin on the sample pressing piston.
Advantageous effects
The loading mode of the cement soil uniaxial tensile tester is strain control, compared with the traditional uniaxial tensile tester, the cement soil uniaxial tensile tester can measure a complete cement soil tensile stress-strain relation curve and analyze the influence of the loading rate on the tensile property of cement soil, so that the loading rate with the minimum influence on the test of the tensile strength of a cement soil sample is selected by comparison;
the cement-soil uniaxial tensile tester provided by the invention adopts the variable cross-section symmetrical structure die with large two ends and small middle part to stretch the sample, and the tensile stress is uniformly transmitted to the two ends of the sample through the relative friction between the sample at the variable cross-section and the die.
The cement soil uniaxial tensile tester adopts the variable cross-section symmetrical structure die with large two ends and small middle part to stretch the sample, the position of the fracture surface and the area of the fracture surface of the sample are fixed, the phase connection point of the sample at the position with the minimum area of the middle section of the die is uniformly fractured, no clamp is needed to be added at the two ends of the die, and the test repeatability is good;
the cement soil uniaxial tensile tester provided by the invention is not only suitable for measuring pure soil with lower tensile strength, but also suitable for cement solidified soil and fiber reinforced soil with higher tensile strength, and has wider applicability.
The invention adopts the sample pressing piston with the same size as the sample pressing mould to press the sample in the whole area, so that the stress on each part of the sample is uniform, no artificial weak surface is ensured in the stretching direction, and the reliability of the test result is improved.
The cement soil uniaxial tensile tester provided by the invention has the advantages of simple structure, convenience in operation, higher precision, strong repeatability and reliable data.
Drawings
FIG. 1 is a front view of a uniaxial cement soil tensile testing apparatus according to the present invention;
FIG. 2 is a top view of the uniaxial cement soil tensile testing apparatus of the present invention;
FIG. 3 is a schematic view of a sample pressing mold according to the present invention;
FIG. 4 is a schematic view of a sample pressing piston according to the present invention;
FIG. 5 is a diagram of uniaxial tension numerical simulation stress distribution of cement soil according to the present invention;
FIG. 6 is a diagram of uniaxial tension numerical simulation strain distribution of cement soil according to the present invention;
FIG. 7 is a diagram showing the practical effect of uniaxial stretching of cement soil according to the present invention;
in the figure: 1. the device comprises a test main body platform, 2, a power loading system, 3, a measuring system, 4, a positioning and stretching system, 5, a motor, 6, a power transmission shaft, 7, a control box, 8, a tension sensor, 9, a displacement sensor, 10, a data collector, 11, a guide sliding die end, 12, a fixed die end, 13, a sliding platform plate, 14, a fixed platform plate, 15, a pulley, 16, a rail base plate, 17, a first fixing screw, 18, a first connecting bolt, 19, a second connecting bolt, 20, a fixed baffle plate, 21, a cement soil sample, 22, a first connecting rod, 23, a second fixing screw, 24, a third fixing screw, 25, a second connecting rod, 26, a sample pressing die, 27, a sample pressing piston, 28, a piston hole, 29, a positioning hole, 30 and a positioning pin.
Detailed Description
In order to make the purpose and technical solution of the embodiments of the present invention clearer, the technical solution of the embodiments of the present invention will be clearly and completely described below with reference to the drawings of the embodiments of the present invention. It is to be understood that the embodiments described are only a few embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the described embodiments of the invention without any inventive step, are within the scope of protection of the invention.
The invention is composed of four parts as a whole: the test device comprises a test main body platform 1, a power loading system 2, a measuring system 3 and a sample positioning and stretching system 4, wherein the power loading system 2, the measuring system 3 and the sample positioning and stretching system 4 are all arranged on the test main body platform 1.
As shown in fig. 1 and 2, the power loading system 2 is composed of a motor 5, a power transmission shaft 6 and a control box 7, the measuring system 3 is composed of five parts, namely a tension sensor 8, a first connecting rod 22, a displacement sensor 9, a data collector 10 and a second connecting bolt 19, and the sample positioning and stretching system 4 is composed of a guide sliding mold end 11, a fixed mold end 12, a sliding platform plate 13, a fixed platform plate 14, a pulley 15, a rail backing plate 16, a connecting rod 25, a fixed baffle plate 20, a first connecting bolt 18, a first fixed screw 17, a second fixed screw 23 and a third fixed screw 24.
The side of the motor 5 is connected with a control box 7 through a lead, and the control box 7 is used for controlling the on-off and the loading rate adjustment of the motor 5. The motor 5 is a speed regulating motor, and can realize strain control type loading according to test requirements. The power take off end of motor 5 transmission conversion links to each other with 6 one end of power transmission shaft, the other end of power transmission shaft 6 links to each other with measuring system 3's force sensor 8, force sensor 8's effect is the pulling force that measuring test in-process cement soil sample 21 received, force sensor 8 leads the slip mould end 11 center with the first half of sample location tensile system 4's mould through connecting rod one 22 and connecting bolt 19 and links to each other, guarantee power transmission shaft 6, force sensor 8, the center of connecting rod one 22 and cement soil sample 21 four is located same altitude level, force sensor 8 can pass through connecting rod one 22, connecting bolt two 19 slides with direction slip mould end 11 together. A displacement sensor 9 is arranged in front of the guide slide die end 11 and serves to measure the deformation of the test specimen 21 under tension during the test.
The tension sensor 8 and the displacement sensor 9 are connected with the data collector 10 through wires. The front half of the mould is fixed on a sliding platform plate 13 of the sample positioning and stretching system 4, and a pulley 15 is arranged between the sliding platform plate 13 and a rail backing plate 16, and the function of the pulley is to reduce friction. The back half part of the mould is arranged on the fixed platform plate 14, the fixed screw II 23 and the fixed screw III 24 are fixed and connected with the fixed platform plate 14 and the track backing plate 16, the fixed mould end 12 is connected with the back fixed baffle plate 20 of the fixed platform plate 14 through the connecting rod 25 and the connecting bolt I18, and the cement soil sample 21 is arranged in a space enclosed by the guide sliding mould end 11 and the fixed mould end 12.
The drawing die consists of two parts which are symmetrical front and back, the two parts are completely disconnected, the size of the cement soil sample 21 is consistent with the internal size of the drawing die, the front part and the back part of the drawing die are respectively connected with the power transmission shaft 6 and the rear fixed baffle 20, and the centers of the joints of the three parts are positioned at the same horizontal height. When the front half part of the drawing die is pulled, the rear half part does not displace along with the movement, and the tensile stress acts on the middle minimum section position of the sample.
As shown in fig. 3 and 4: the cement soil sample 21 is prepared through a sample pressing mold 26 and a sample pressing piston 27, a piston hole 28 is formed in the middle of the sample pressing mold 26, the size of the piston hole is matched with that of the sample pressing piston 27, a positioning hole 29 is formed in the sample pressing piston 27, and a positioning pin 30 is placed in the positioning hole 29 and used for flexibly controlling the sample pressing piston 27 to be taken and placed and the accuracy of the sample pressing height. The cement soil sample 21 has a symmetrical structure with two large ends and a small middle, the variable cross-section rate of the sample is small, and the effect of stress concentration on experimental results can be reduced.
The included angle of the variable cross sections at the two ends of the die is about 81 degrees, the angle is relatively large enough to ensure that the change rate of the variable cross sections in the stretching process is relatively slow, numerical simulation effect graphs 5 and 6 are supplemented to the graph, the stress and strain distribution graphs of the dimensional model are found to be uniform in distribution and consistent with the expected stretching effect of the die from the stress and strain distribution graphs obtained by numerical simulation, the stretching fracture surface is located at the position with the minimum cross section from the actual stretching effect graph of fig. 7, the stretching fracture surface is located at the separation position between the guide sliding die and the fixed die, and the position of the stretching fracture surface is unique.
The working principle mode of the invention is as follows:
the motor 5 of the power loading system 2 drags the tension sensor 8 connected with the power loading system to move towards the left side of the test main body platform 1 at a constant displacement rate through the power transmission shaft 6, and further, tensile stress is applied to the cement soil sample 21 in the mould through the connecting rod 22 and the connecting bolt II 19, and the tensile stress and tensile deformation of the cement soil sample 21 are collected and stored through the data collector 10 connected with the tension sensor 8 and the displacement sensor 9.
The cement soil sample test method comprises the following steps:
(1) placing a sample pressing mold 26 in a tray with an acrylic plate at the bottom, then placing the mixed cement soil into the sample pressing mold 26 for three times and placing a sample pressing piston 27, placing the tray on a vibration table after the first two sample installations to vibrate for two minutes and scrape the surface, inserting a positioning pin 30 into a positioning hole 29 pre-opened on the sample pressing piston 27 according to the height of a sample required by design at the last time, placing the sample pressing piston 27 in a piston hole 28, placing the cement soil into the sample pressing mold 26 to the required height and flattening the surface;
(2) the cured soil cement sample 21 is pushed out from the sample pressing mold 26 by using a sample pressing piston 27 and is placed in a space enclosed by the guide sliding mold end 11 and the fixed mold end 12, the guide sliding mold end 11 of the front half part of the stretching mold is connected with a first connecting rod 22, and the fixed mold end 12 of the rear half part of the stretching mold is connected with a rear fixed baffle 20 of the fixed platform plate 14 through a second connecting rod 25 and a connecting bolt 18. When the front half part of the drawing die is pulled, the rear half part does not displace along with the movement, and the tensile stress acts on the middle minimum section position of the sample.
(3) The control box 7 is operated to set a tensile displacement rate, then the values of the tension sensor 8 and the displacement sensor 9 are reset, the power supply of the motor 5 is switched on, a start key is pressed down, a uniform-speed tensile test is carried out, and meanwhile, the data collector 10 collects tensile stress and displacement change data until the cement soil sample is completely broken;
(4) and (3) removing the broken cement soil sample 21, and performing uniaxial tension test on the new cement soil sample 21 according to the steps (1), (2) and (3) until the test work of all the cement soil samples is completed.
The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are included in the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.
Claims (10)
1. The utility model provides a soil cement uniaxial tension test appearance which characterized in that: the device comprises a test main body platform, a power loading system, a measuring system and a sample positioning and stretching system; a power loading system, a measuring system and a sample positioning and stretching system are arranged on the test main body platform; the sample positioning and stretching system is used for placing the detected cement soil sample; the dynamic loading system drives the sample positioning and stretching system, and the measuring system is used for acquiring the tension and displacement change data of the sample positioning and stretching system.
2. The soil cement uniaxial tensile tester according to claim 1, wherein: the power loading system comprises a motor, a power transmission shaft and a control box; the motor is controlled by the control box, and a driving end of the motor is provided with a power transmission shaft.
3. The soil cement uniaxial tensile tester according to claim 1, wherein: the measuring system comprises a first connecting rod, a displacement sensor, a tension sensor, a data collector and a connecting bolt; the measuring system is connected with the power loading system through a first connecting rod, the displacement sensor is arranged on the test main body platform, a baffle is fixed on the first connecting rod, the baffle is in contact with the displacement sensor, and the acquisition end of the data acquisition unit is respectively connected with the displacement sensor and the tension sensor.
4. The soil cement uniaxial tensile tester according to claim 2 or 3, wherein: and a power transmission shaft in the power loading system is connected with a connecting rod I in the measuring system through a tension sensor.
5. The soil cement uniaxial tensile tester according to claim 1, wherein: the sample positioning and stretching system comprises a guide sliding die end, a fixed die end, a sliding platform plate, a fixed platform plate, a pulley and a rail base plate; the rail backing plate is fixed on the test main body platform through a fixing bolt, and a guide sliding die end and a fixed die end are arranged on the rail backing plate; the guide sliding mold end and the fixed mold end are spliced in a non-fixed mode; placing a cement soil sample in a space enclosed by splicing the guide sliding mold end and the fixed mold end;
a pulley for guiding is arranged between the guiding sliding die end and the rail backing plate, and the fixed die end and the rail backing plate are fixed with each other through a fixing bolt;
the die cavities in the guide sliding die end and the fixed die end are trapezoidal die cavities, and the furled ends of the trapezoidal die cavities in the guide sliding die end and the fixed die end are mutually spliced.
6. The soil cement uniaxial tensile tester according to claim 5, wherein: and a second connecting rod is arranged between the fixed baffle and the fixed mould end.
7. The soil cement uniaxial tensile tester according to claim 1, wherein: the cement soil sample is prepared through a sample pressing mold and a sample pressing piston; the inner cavity of the sample pressing mold is of a variable cross-section symmetrical structure with two large ends and a small middle part; the sample pressing mold is provided with a piston hole, and the size of the piston hole is matched with that of the sample pressing piston.
8. The soil cement uniaxial tension tester as set forth in claim 7, wherein: the sample pressing piston is provided with a positioning hole, and the positioning pin is arranged in the positioning hole of the sample pressing piston.
9. A test method using the soil cement uniaxial tension tester of any one of claims 1 to 8, characterized in that: the method comprises the following steps:
step one, preparing a sample: placing a sample pressing mold in a tray with an acrylic plate at the bottom, then loading the mixed cement soil into the mold for three times and placing a sample pressing piston, placing the tray on a vibrating table after the first two sample loading, vibrating for two minutes and scratching the surface, and finally loading the cement soil into the mold to a required height and smoothing the surface;
step two, loading a sample: pushing the cured cement soil sample out of the sample pressing mold by using a sample pressing piston, and placing the sample in a space enclosed by a guide sliding mold end and a fixed mold end;
step three, setting a test tensile value and executing a test: clearing the values of a displacement sensor and a tension sensor, setting a tensile displacement rate through a control box, performing a uniform-speed tensile test through a power transmission shaft, and acquiring tensile stress and displacement data through a data acquisition unit until a cement soil sample is completely broken;
and step four, repeating the step three to carry out tests aiming at different tests until all the test samples are tested.
10. The testing method of the soil cement uniaxial tension tester according to claim 9, characterized in that: in the first step, the height of the prepared sample is controlled by using a positioning pin on a sample pressing piston.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110167961.1A CN112964553A (en) | 2021-02-07 | 2021-02-07 | Cement soil uniaxial tension tester and testing method |
Applications Claiming Priority (1)
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| CN113533034A (en) * | 2021-08-30 | 2021-10-22 | 石家庄铁道大学 | Soil body tensile test device and soil body tensile test method |
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