CN111024503A - Annular test device for measuring internal tensile stress and crack development of soil body in real time - Google Patents

Annular test device for measuring internal tensile stress and crack development of soil body in real time Download PDF

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CN111024503A
CN111024503A CN201911393337.2A CN201911393337A CN111024503A CN 111024503 A CN111024503 A CN 111024503A CN 201911393337 A CN201911393337 A CN 201911393337A CN 111024503 A CN111024503 A CN 111024503A
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soil sample
annular
tensile stress
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soil
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霍继炜
姜彤
翟国政
高宇甲
李俊杰
赵金玓
朱云江
张俊然
陈金权
胡魁
韩明涛
余斌
焦继伟
孟旭
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North China University of Water Resources and Electric Power
Fourth Construction Co Ltd of China Construction Seventh Engineering Co Ltd
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Fourth Construction Co Ltd of China Construction Seventh Engineering Co Ltd
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    • G01N3/00—Investigating strength properties of solid materials by application of mechanical stress
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    • 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
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    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
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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
    • G01N2203/0058—Kind of property studied
    • G01N2203/006—Crack, flaws, fracture or rupture
    • G01N2203/0062—Crack or flaws
    • G01N2203/0066—Propagation of crack

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Abstract

The invention discloses an annular test device for measuring internal tensile stress and crack development of a soil body in real time, which comprises a soil sample tensile unit, a stress-strain test unit and an image acquisition unit, the soil sample tension unit is an annular soil sample tension unit, the annular soil sample tension unit comprises an annular soil sample containing device, a soil sample crack capturing layer and a weighing device, wherein the weighing device is provided with an annular soil sample containing device, the annular soil sample containing device is internally provided with an annular soil sample, the top layer of the annular soil sample is detachably provided with a soil sample crack capturing layer, the soil sample crack capturing layer is provided with a camera device, the camera device is electrically connected with the image acquisition unit, the annular soil sample containing device is electrically connected with the stress-strain testing unit, and the annular soil sample containing device has the advantages of being quick in installation, convenient to test and small in occupied area.

Description

实时量测土体的内部拉应力及裂隙发育的环形试验装置A ring test device for real-time measurement of soil internal tensile stress and crack development

技术领域technical field

本发明属于岩土工程技术领域，具体涉及一种实时量测土地内部拉应力及裂隙发育的环形试验装置。The invention belongs to the technical field of geotechnical engineering, and in particular relates to a ring-shaped test device for real-time measurement of the internal tensile stress and the development of cracks in the soil.

背景技术Background technique

在岩土工程领域中，抗拉强度和拉应力是控制土体裂隙发展的两个主要因素，土地在干化的过程中，内部拉应力变大，当拉应力超过抗拉强度时，土体出现裂缝，了解土体中拉应力增加导致裂纹萌生的机理至关重要。In the field of geotechnical engineering, tensile strength and tensile stress are the two main factors that control the development of soil fissures. During the drying process of the soil, the internal tensile stress increases. When the tensile stress exceeds the tensile strength, the soil When cracks occur, it is crucial to understand the mechanism by which increased tensile stress in the soil leads to crack initiation.

通常采用夹具装置和三轴仪器来测量和预测抗拉强度，这些传统土体抗拉强度测试方法均通过向土体施加外部荷载的方式使土体发生抗拉破坏，而导致无法真正测得土体内部的拉应力变化，且采用的方形或圆柱形试样均为密闭土地，较难保证所测拉应力的均匀性。Fixtures and triaxial instruments are usually used to measure and predict the tensile strength. These traditional soil tensile strength testing methods all cause the soil to undergo tensile failure by applying external loads to the soil, resulting in the inability to truly measure the soil. The tensile stress inside the body varies, and the square or cylindrical specimens used are all closed ground, so it is difficult to ensure the uniformity of the measured tensile stress.

发明内容SUMMARY OF THE INVENTION

为解决上述技术问题，本发明提供一种实时量测土体的内部拉应力及裂隙发育的环形试验装置，具有安装快速，测试便捷和装置占地面积少的特点。In order to solve the above technical problems, the present invention provides a ring-shaped test device for real-time measurement of the internal tensile stress of soil and the development of cracks, which has the characteristics of fast installation, convenient testing and small footprint of the device.

实时量测土体的内部拉应力及裂隙发育的环形试验装置，包括土样受拉单元、应力应变测试单元和图像采集单元，所述土样受拉单元为环形土样受拉单元，所述环形土样受拉单元包括环形土样盛放装置、土样裂隙捕捉层和称重装置，其中，所述称重装置上设置有环形土样盛放装置，所述环形土样盛放装置内盛放有环形土样，所述环形土样的顶层可拆卸设置有土样裂隙捕捉层，所述土样裂隙捕捉层上设置有摄像装置，所述摄像装置与图像采集单元电连接，所述环形土样盛放装置与应力应变测试单元电连接。A ring test device for real-time measurement of internal tensile stress and crack development of soil, including a soil sample tension unit, a stress-strain test unit and an image acquisition unit, the soil sample tension unit is an annular soil sample tension unit, and the The annular soil sample tension unit includes an annular soil sample holding device, a soil sample fissure capturing layer and a weighing device, wherein the weighing device is provided with an annular soil sample holding device, and the annular soil sample holding device is arranged in the annular soil sample holding device. A ring-shaped soil sample is contained, the top layer of the ring-shaped soil sample is detachably provided with a soil sample fissure capture layer, a camera device is arranged on the soil sample fissure capture layer, and the camera device is electrically connected to the image acquisition unit, and the The annular soil sample holding device is electrically connected with the stress-strain testing unit.

所述土样裂隙捕捉层为砂土层。The soil sample fissure capturing layer is a sandy soil layer.

所述称重装置为天平。The weighing device is a balance.

所述环形土样盛放装置包括外环和内环，所述外环和内环均为PVC材料围合组成，所述外环和内环内均涂抹有润滑油。The annular soil sample holding device includes an outer ring and an inner ring, the outer ring and the inner ring are both enclosed by PVC material, and the outer ring and the inner ring are coated with lubricating oil.

所述内环内可拆卸设置有应变片，所述环形土样盛放装置通过应变片与应力应变测试单元电连接。A strain gauge is detachably arranged in the inner ring, and the annular soil sample holding device is electrically connected to the stress-strain testing unit through the strain gauge.

所述内环内的中心位置处均匀相对可拆卸设置有四片应变片，所述应变片为电阻式应变片。Four strain gauges are evenly and detachably arranged at the central position in the inner ring, and the strain gauges are resistive strain gauges.

所述应力应变测试单元包括温度显示器、含水率显示器和四通道应变数据采集器，所述应变片与四通道应变数据采集器电连接，所述温度显示器和含水率显示器均设置在称重装置上，所述温度显示器和含水率显示器均与四通道应变数据采集器电连接。The stress-strain testing unit includes a temperature display, a water content display and a four-channel strain data collector, the strain gauge is electrically connected to the four-channel strain data collector, and both the temperature display and the water content display are arranged on the weighing device , the temperature display and the water content display are both electrically connected with the four-channel strain data collector.

所述温度显示器和含水率显示器为液晶显示屏或数码管种的任意一种，所述四通道应变数据采集器中包括具有数据计算处理功能的芯片，所述数据计算处理功能的芯片为MCU、PC机、PLC或工控机中的任意一种。The temperature display and the moisture content display are any one of liquid crystal display or digital tube, and the four-channel strain data collector includes a chip with data calculation and processing functions, and the chips with data calculation and processing functions are MCU, Any one of PC, PLC or industrial computer.

所述摄像装置为CCD高速相机，与所述CCD高速相机配对设置有相机支架，所述相机支架设置在称重装置一侧，所述CCD高速相机与图像采集单元电连接。The imaging device is a CCD high-speed camera, and is paired with the CCD high-speed camera and is provided with a camera bracket, the camera bracket is arranged on one side of the weighing device, and the CCD high-speed camera is electrically connected to the image acquisition unit.

所述图像采集单元为PIV测试系统。The image acquisition unit is a PIV test system.

本发明公开了一种实时量测土体的内部拉应力及裂隙发育的环形试验装置，采用环形土样盛放装置，在内环上安装应变片测量拉伸应变得到内部拉应力变化，得到土体的抗拉强度，通过环形土样上层的土样裂隙捕捉层与摄像装置和土样采样装置配合，描述了裂隙的发育过程，本发明将饱和土样静置，使其自然失水，用应变片测得土样在此过程中的拉应力，能够更加真实反应拉应力的变化过程，使得对土体抗拉强度的预测更加可靠，环形土样盛放装置，减少了装置的占地面积，具有外形新颖，简单美观，便于安装应变片的效果，而且使得对抗拉强度的量测、裂隙的捕捉、位移的计算具有方便快捷的有益效果。The invention discloses an annular test device for real-time measurement of the internal tensile stress of soil and the development of fissures. An annular soil sample holding device is used, and strain gauges are installed on the inner ring to measure the tensile strain to obtain the change of the internal tensile stress, and the soil sample is obtained. The tensile strength of the body is described by the soil sample fissure capture layer on the upper layer of the annular soil sample in coordination with the camera device and the soil sample sampling device to describe the development process of the fissures. The strain gauge measures the tensile stress of the soil sample in this process, which can more truly reflect the change process of the tensile stress, making the prediction of the tensile strength of the soil more reliable. The annular soil sample storage device reduces the footprint of the device The utility model has the advantages of novel appearance, simple and beautiful appearance, easy installation of strain gauges, and convenient and quick beneficial effects of measuring tensile strength, capturing cracks, and calculating displacement.

附图说明Description of drawings

图1是本发明的整体结构示意图。Figure 1 is a schematic diagram of the overall structure of the present invention.

图2是本发明的环形土样盛放装置、称重装置和应力应变测试单元的俯视结构示意图。2 is a schematic top view of the structure of the annular soil sample holding device, the weighing device and the stress-strain testing unit of the present invention.

其中，附图标记如下：Among them, the reference numerals are as follows:

1. 环形土样，2. 内环，3. 外环，4. 应变片，5. 温度显示器，6. 含水率显示器，7. 称重装置，8. 四通道应变数据采集器，9. 摄像装置，10. 图像采集单元，11. 应力应变测试单元，12. 相机支架，13. 环形土样盛放装置。1. Ring soil sample, 2. Inner ring, 3. Outer ring, 4. Strain gauge, 5. Temperature display, 6. Water content display, 7. Weighing device, 8. Four-channel strain data collector, 9. Camera device, 10. image acquisition unit, 11. stress-strain testing unit, 12. camera bracket, 13. annular soil sample holding device.

具体实施方式Detailed ways

下面将结合本发明中的附图，对本发明实施例中的技术方案进行清楚、完整地描述。显然，所描述的实施例仅是本发明一部分实施，而不是全部的实施，基于本发明的实施例，本领域普通技术人员在没有做、出创造性劳动前提下所获得的所有其它实施例，都属于本发明保护的范围。The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the present invention. Obviously, the described embodiments are only a part of the implementation of the present invention, rather than the entire implementation. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work are all belong to the protection scope of the present invention.

如图1-2所示，实时量测土体的内部拉应力及裂隙发育的环形试验装置，包括土样受拉单元、应力应变测试单元11和图像采集单元10，所述土样受拉单元为环形土样受拉单元，所述环形土样受拉单元包括环形土样盛放装置13、土样裂隙捕捉层和称重装置7，其中，所述称重装置7上设置有环形土样盛放装置13，所述环形土样盛放装置13内盛放有环形土样1，所述环形土样1的顶层可拆卸设置有土样裂隙捕捉层，所述土样裂隙捕捉层上设置有摄像装置9，所述摄像装置9与图像采集单元10电连接，所述环形土样盛放装置13与应力应变测试单元11电连接。As shown in Figure 1-2, the ring test device for real-time measurement of the internal tensile stress of soil and the development of fissures includes a soil sample tension unit, a stress-strain testing unit 11 and an image acquisition unit 10. The soil sample tension unit It is an annular soil sample tension unit, and the annular soil sample tension unit includes an annular soil sample holding device 13, a soil sample fissure capture layer and a weighing device 7, wherein the weighing device 7 is provided with an annular soil sample A holding device 13, the annular soil sample holding device 13 contains an annular soil sample 1, the top layer of the annular soil sample 1 is detachably provided with a soil sample fissure capture layer, and a soil sample fissure capture layer is provided on the soil sample fissure capture layer. There is a camera device 9 , the camera device 9 is electrically connected to the image acquisition unit 10 , and the annular soil sample holding device 13 is electrically connected to the stress-strain testing unit 11 .

所述土样裂隙捕捉层为砂土层。The soil sample fissure capturing layer is a sandy soil layer.

所述环形土样盛放装置13包括外环3和内环2，所述外环3和内环2均为PVC材料围合组成，所述外环3和内环2内均涂抹有润滑油。The annular soil sample holding device 13 includes an outer ring 3 and an inner ring 2, the outer ring 3 and the inner ring 2 are both enclosed by PVC materials, and the outer ring 3 and the inner ring 2 are coated with lubricating oil. .

所述的环形土样盛放装置13尺寸为：内环2直径5.5cm，外环3直径15.24cm，高度4.1 cm，内环2使用材料为PVC，厚度为0.5cm，外环3使用材料为PVC，其厚度为1.65cm。The dimensions of the annular soil sample holding device 13 are: the diameter of the inner ring 2 is 5.5 cm, the diameter of the outer ring 3 is 15.24 cm, and the height is 4.1 cm, the material used for the inner ring 2 is PVC, the thickness is 0.5 cm, and the material used for the outer ring 3 is PVC, its thickness is 1.65cm.

所示环形土样盛放装置13的底部、内环2外周、外环3内周均应涂上润滑油，以减小装样过程中产生的摩擦，并保证土样的侧面和底部具有一定的不透水性。在开始试验之前，用塑料薄膜从底部密封土壤样本，并用橡胶薄膜从圆周密封，以保持土壤样本径向收缩时均匀收缩的密封性。The bottom of the shown annular soil sample holding device 13, the outer circumference of the inner ring 2, and the inner circumference of the outer ring 3 should be coated with lubricating oil to reduce the friction generated during the loading process and ensure that the sides and bottom of the soil sample have certain unevenness. Water permeability. Before starting the test, the soil samples were sealed from the bottom with plastic film and from the circumference with rubber film to maintain the tightness of the soil samples as they shrink radially evenly.

所述称重装置7为天平，天平是测量环形盛放装置13中的土样含水量变化的承载体，砂土层均匀洒于环形土样的表面，用于捕捉土体裂隙的产生，计算裂隙的位移。The weighing device 7 is a balance, and the balance is a carrier for measuring the water content change of the soil sample in the annular storage device 13. The sand layer is evenly sprinkled on the surface of the annular soil sample to capture the generation of soil fissures and calculate Displacement of the fissure.

所述的天平7用于承载土样，并记录土样含水量的变化；天平的量程为5000g，精度为0.01g。The balance 7 is used to carry the soil sample and record the change of the water content of the soil sample; the scale of the balance is 5000g, and the precision is 0.01g.

所述内环2内可拆卸设置有应变片4，所述环形土样盛放装置13通过应变片4与应力应变测试单元11电连接。A strain gauge 4 is detachably disposed in the inner ring 2 , and the annular soil sample holding device 13 is electrically connected to the stress-strain testing unit 11 through the strain gauge 4 .

所述内环2内的中心位置处均匀相对可拆卸设置有四片应变片4，所述应变片4为电阻式应变片。Four strain gauges 4 are uniformly and detachably disposed at the center position in the inner ring 2 , and the strain gauges 4 are resistive strain gauges.

所述的测量拉应力的四个应变片4选用四分之一桥电阻式应变片，电阻大小为350Ω，四个应变片相对位于矩形的一角，贴于土样PVC内环表面中央，高度为2.04cm。The four strain gauges 4 for measuring tensile stress are made of quarter-bridge resistive strain gauges with a resistance of 350Ω. The four strain gauges are located at one corner of the rectangle relatively, and are attached to the center of the surface of the PVC inner ring of the soil sample, with a height of 350Ω. 2.04cm.

所述应力应变测试单元11包括温度显示器5、含水率显示器6和四通道应变数据采集器8，所述应变片4与四通道应变数据采集器8电连接，所述温度显示器5和含水率显示器6均设置在称重装置7上，所述温度显示器5和含水率显示器6均与四通道应变数据采集器8电连接。The stress-strain testing unit 11 includes a temperature display 5, a water content display 6 and a four-channel strain data collector 8, the strain gauge 4 is electrically connected to the four-channel strain data collector 8, the temperature display 5 and the water content display 6 are arranged on the weighing device 7 , and the temperature display 5 and the water content display 6 are both electrically connected to the four-channel strain data collector 8 .

所述四通道应变数据采集器8与四个应变片4相连，位于环形土样盛放装置1的一侧，能够连续记录应变随时间的变化，其应变值可通过公式转换为应力。所述公式如下：The four-channel strain data collector 8 is connected with four strain gauges 4 and is located on one side of the annular soil sample holding device 1 , which can continuously record the change of strain with time, and the strain value can be converted into stress by formula. The formula is as follows:

Figure DEST_PATH_IMAGE001
Figure DEST_PATH_IMAGE001

其中，σ tm 为所求拉应力，ε(t)为应变片平均示数，R or 为内环直径，R ir 为外环直径，R os 为环形土样外直径，E r 为PVC材料的弹性模量。Among them, σ tm is the required tensile stress, ε ( t ) is the average indication of the strain gauge, R or is the diameter of the inner ring, R ir is the diameter of the outer ring, Ro s is the outer diameter of the annular soil sample, and E r is the diameter of the PVC material. Elastic Modulus.

所述温度显示器5和含水率显示器6为液晶显示屏或数码管种的任意一种，所述四通道应变数据采集器8中包括具有数据计算处理功能的芯片，所述数据计算处理功能的芯片为MCU、PC机、PLC或工控机中的任意一种。The temperature display 5 and the moisture content display 6 are any one of liquid crystal display or digital tube, and the four-channel strain data collector 8 includes a chip with a data calculation and processing function. It is any one of MCU, PC, PLC or industrial computer.

所述温度显示器5显示温度精度为1℃，所述含水率显示器6，显示含水率精度为0.1%，含水率数值通过起始状态重量值与最终状态的重量值获得。The temperature display 5 shows a temperature accuracy of 1°C, the moisture content display 6 shows a moisture content accuracy of 0.1%, and the moisture content value is obtained from the initial state weight value and the final state weight value.

所述摄像装置9为CCD高速相机，与所述CCD高速相机配对设置有相机支架12，所述相机支架12设置在称重装置7一侧，所述CCD高速相机与图像采集单元10电连接。The camera device 9 is a CCD high-speed camera, which is paired with the CCD high-speed camera and is provided with a camera bracket 12 .

所述的CCD高速相机分辨率为1626pixel×1236pixel，像素尺寸为4.4μm×4.4μm，曝光时间为100μs×80ms，采集速率可达200fps，同时提供了Camlink专用接口。The resolution of the CCD high-speed camera is 1626pixel×1236pixel, the pixel size is 4.4μm×4.4μm, the exposure time is 100μs×80ms, the acquisition rate can reach 200fps, and a special interface for Camlink is provided.

所述砂土均匀的洒在环形土样的表面，顶部的摄像装置9每隔10min记录一次，结合PIV系统，用于观察裂隙产生后的发育情况，计算裂隙的位移，并对裂隙的位移进行记录处理。The sand is evenly sprinkled on the surface of the annular soil sample, and the camera device 9 at the top records every 10 minutes. Combined with the PIV system, it is used to observe the development of the cracks after they are generated, calculate the displacement of the cracks, and carry out the displacement of the cracks. record processing.

所述图像采集单元10为PIV测试系统。The image acquisition unit 10 is a PIV testing system.

所述实时量测土体内部拉应力及裂隙发育的环形试验装置，其试验方法具体如下：The test method of the annular test device for real-time measurement of internal tensile stress and crack development in soil is as follows:

a.在外环3和内环2的内表面涂上一层薄薄的润滑油，将一定干密度和含水率的土分两次加入直径为15.24 cm的外环3中，每层用直径为2.55cm的木棒进行击实，第一层击实高度为2.05cm，第二层击实高度为4.1cm。采用小刀和薄壁钢环在圆柱形土样的中心挖一个半径直径为5.5cm的孔，将PVC内环2缓慢地插入孔中。为防止水分蒸发，试样的侧面和底部涂抹有润滑油。a. Coat the inner surfaces of outer ring 3 and inner ring 2 with a thin layer of lubricating oil, add soil with a certain dry density and moisture content into outer ring 3 with a diameter of 15.24 cm in two times, each layer with a diameter of For 2.55cm sticks, the compaction height of the first layer is 2.05cm, and the compaction height of the second layer is 4.1cm. Use a knife and a thin-walled steel ring to dig a hole with a radius of 5.5 cm in the center of the cylindrical soil sample, and slowly insert the PVC inner ring 2 into the hole. To prevent evaporation of water, the sides and bottom of the specimen are coated with lubricating oil.

b. 将制备好的环形土样放置在天平上，通过质量的变化换算含水率的改变。b. Place the prepared annular soil sample on the balance, and convert the change in moisture content by the change in mass.

c.在内环2表面对称依次张贴四个应变片4，将应变片4的连接线交接在一起，与四通道应变数据采集器8相连。c. Post four strain gauges 4 symmetrically on the surface of the inner ring 2 in sequence, connect the connecting wires of the strain gauges 4 together, and connect to the four-channel strain data collector 8 .

d.将环形土样放置于天然状态下，让其自然失水。应变片4的数据由应四通道应变数据采集器8读出，获得土体拉应力。d. Place the annular soil sample in a natural state and let it lose water naturally. The data of the strain gauge 4 is read out by the four-channel strain data collector 8 to obtain the soil tensile stress.

e.装置顶部的摄像装置每10min记录一次数据，实时量测土体在此过程中的状态变化。e. The camera at the top of the device records data every 10 minutes, and measures the state change of the soil in real time during this process.

f.通过此过程，可以得到土体内部拉应力的变化规律，并得到土体抗拉强度，为预测裂隙出现提供拉应力参考值。f. Through this process, the variation law of the internal tensile stress of the soil body can be obtained, and the tensile strength of the soil body can be obtained, which can provide a reference value of the tensile stress for predicting the occurrence of cracks.

此外，在环形土体的表面均匀的洒上白色砂土，增添使用图像数据显示器，结合PIV测量系统的处理方法，捕捉表面土体的位移，得到在天然干化过程中，裂隙不断发育的动态过程。本发明方案所公开的技术手段不仅限于上述实施方式所公开的技术手段，还包括由以上技术特征任意组合所组成的技术方案。应当指出，对于本技术领域的普通技术人员来说，在不脱离本发明原理的前提下，还可以做出若干改进和润饰，这些改进和润饰也视为本发明的保护范围。In addition, the surface of the annular soil is evenly sprinkled with white sand, and the image data display is added. Combined with the processing method of the PIV measurement system, the displacement of the surface soil is captured, and the dynamic development of cracks during the natural drying process can be obtained. process. The technical means disclosed in the solution of the present invention are not limited to the technical means disclosed in the above embodiments, but also include technical solutions composed of any combination of the above technical features. It should be pointed out that for those skilled in the art, without departing from the principle of the present invention, several improvements and modifications can be made, and these improvements and modifications are also regarded as the protection scope of the present invention.

Claims (10)

1. The annular test device for measuring the internal tensile stress and the crack development of the soil body in real time comprises a soil sample tensile unit, a stress-strain test unit (11) and an image acquisition unit (10), and is characterized in that: the soil sample tension unit is an annular soil sample tension unit, the annular soil sample tension unit comprises an annular soil sample containing device (13), a soil sample crack capturing layer and a weighing device (7), wherein the weighing device (7) is provided with the annular soil sample containing device (13), an annular soil sample (1) is contained in the annular soil sample containing device (13), the top layer of the annular soil sample (1) is detachably provided with the soil sample crack capturing layer, the soil sample crack capturing layer is provided with a camera device (9), the camera device (9) is electrically connected with an image acquisition unit (10), and the annular soil sample containing device (13) is electrically connected with a stress-strain testing unit (11).
2. The annular test device for measuring the internal tensile stress and the crack development of a soil body in real time according to claim 1, wherein: the soil sample crack capturing layer is a sand layer.
3. The annular test device for measuring the internal tensile stress and the crack development of a soil body in real time according to claim 1, wherein: the weighing device (7) is a balance.
4. The annular test device for measuring the internal tensile stress and the crack development of a soil body in real time according to claim 1, wherein: annular soil sample holds device (13) and includes outer ring (3) and inner ring (2), outer ring (3) and inner ring (2) are PVC material and enclose to close to form, lubricating oil has all been paintd in outer ring (3) and inner ring (2).
5. The annular test device for measuring the internal tensile stress and the crack development of a soil body in real time according to claim 4, wherein: can dismantle in inner ring (2) and be provided with foil gage (4), annular soil sample holds device (13) and is connected with stress and strain test unit (11) electricity through foil gage (4).
6. The annular test device for measuring the internal tensile stress and the crack development of a soil body in real time according to claim 5, wherein: the center position department in the inner ring (2) is evenly provided with four foil gauges (4) relatively detachably, foil gauge (4) are resistance-type foil gauges.
7. The annular test device for measuring the internal tensile stress and the crack development of a soil body in real time according to claim 6, wherein: stress strain test unit (11) are including temperature monitor (5), moisture content display (6) and four-channel strain data collector (8), foil gage (4) are connected with four-channel strain data collector (8) electricity, temperature monitor (5) and moisture content display (6) all set up on weighing device (7), temperature monitor (5) and moisture content display (6) all are connected with four-channel strain data collector (8) electricity.
8. The annular test device for measuring the internal tensile stress and the crack development of a soil body in real time according to claim 7, wherein: the device is characterized in that the temperature display (5) and the moisture content display (6) are any one of a liquid crystal display screen or a nixie tube, the four-channel strain data acquisition unit (8) comprises a chip with a data calculation processing function, and the chip with the data calculation processing function is any one of an MCU, a PC, a PLC or an industrial personal computer.
9. The annular test device for measuring the internal tensile stress and the crack development of a soil body in real time according to claim 1, wherein: the camera device (9) is a CCD high-speed camera, a camera support (12) is arranged in a matching mode with the CCD high-speed camera, the camera support (12) is arranged on one side of the weighing device (7), and the CCD high-speed camera is electrically connected with the image acquisition unit (10).
10. The annular test device for measuring the internal tensile stress and the crack development of a soil body in real time according to claim 1, wherein: the image acquisition unit (10) is a PIV test system.
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