WO2021179335A1 - 真三维应力下高温煤体注水润湿致其裂隙扩展的试验方法 - Google Patents

真三维应力下高温煤体注水润湿致其裂隙扩展的试验方法 Download PDF

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WO2021179335A1
WO2021179335A1 PCT/CN2020/079420 CN2020079420W WO2021179335A1 WO 2021179335 A1 WO2021179335 A1 WO 2021179335A1 CN 2020079420 W CN2020079420 W CN 2020079420W WO 2021179335 A1 WO2021179335 A1 WO 2021179335A1
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water injection
sample
test
main casing
injection hole
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PCT/CN2020/079420
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English (en)
French (fr)
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程卫民
王刚
刘义鑫
孙路路
倪冠华
黄启铭
于岩斌
刘震
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山东科技大学
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Publication of WO2021179335A1 publication Critical patent/WO2021179335A1/zh

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
    • G01N33/22—Fuels; Explosives
    • G01N33/222—Solid fuels, e.g. coal

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  • the invention belongs to the technical field of coal and rock mass simulation tests, and specifically relates to a test method for crack expansion caused by high-temperature coal mass water injection wetting under true three-dimensional stress.
  • Coal is the main energy source in my country.
  • the mining depth of coal in my country is increasing at an average annual rate of 8-10m, while the mining depth in eastern mines, which accounts for 1/3 of the current coal mines, is increasing at an average annual rate of 10-25m.
  • the mine depth reaches 1000m, 50% of the temperature rise in the mine is caused by heat dissipation from the surrounding rock.
  • the problem of mine heat damage has become a major problem in deep mine mining. Studying the impact of water injection into coal and rock mass in deep mines on the temperature field of surrounding rock is of great significance to improving the working environment of underground workers.
  • Coal seam water injection is a common way to cool down. It is to arrange boreholes in a flat or inclined road near the working face. By injecting water into the coal seam, the cold water is injected into the coal to be mined by water pressure, which has the advantages of high efficiency and low cost. At the same time, water injection into the coal seam can also have the effect of displacing gas and reducing dust. In addition, due to the thermal expansion and contraction characteristics of the coal body, when the high temperature problem is under the action of cold water cooling, the internal cracks due to cold shrinkage will further increase the permeability of the coal body and promote the expansion of the cold water wetting range.
  • the traditional method for understanding and analyzing the hydraulic wetting of high-temperature rock mass is mainly numerical simulation. Its advantage is low cost and the boundary conditions can be changed arbitrarily. However, the numerical simulation calculation often hardly reflects the real situation.
  • the existing results show that domestic and foreign scholars have carried out certain indoor experimental research in this field. However, in the existing test equipment, most of the cavity containing the test piece is placed in a water bath or oil bath, or a heating device or heating layer is wound around the cavity of the test piece, which cannot truly restore the heat conduction in engineering practice. Phenomenon. Secondly, in the traditional coal wetness test device, most of them focused on the study of its seepage characteristics, ignoring the fracture damage caused by cold water to the coal.
  • the technical problem to be solved by the present invention is to provide a test method for simulating the expansion of cracks caused by water injection in high temperature coal under the action of true triaxial stress, which is effective for studying the cooling and damage mechanism of water injection wetting on coal Distribute water injection boreholes and lay a theoretical foundation for improving economic benefits.
  • the technical solution adopted by the present invention is: a test method for crack expansion caused by water injection in a high-temperature coal body under true three-dimensional stress, which includes the following steps:
  • Step 2 Drill a water injection hole for the test piece
  • Step three install the water injection pipe
  • Step 4 The sample is installed on the test device of the true triaxial test
  • the true three-axis test device includes a host, a host support component, a slide rail, a slide rail support component, and a servo cylinder.
  • the lower part extends forward and backward, and after passing through the mainframe, it is supported on the ground by the sliding rail support assembly.
  • the mainframe includes a cast-shaped integral ring frame.
  • the outer side is equipped with a cover plate, and the integral ring frame and the cover plate enclose the main frame.
  • At least two heating rods are installed symmetrically on the upper and lower walls of the main frame at intervals of left and right.
  • the inner cavity of the main frame is used for placing samples.
  • the upper, lower, left, right, front, and rear sides of the sample are respectively equipped with sample pads, and a sample moving bracket that can move back and forth on the slide rail is provided under the sample pads located on the lower side;
  • a sample moving bracket that can move back and forth on the slide rail is provided under the sample pads located on the lower side;
  • Below the servo cylinders on the front and rear sides are provided with a cylinder moving bracket that can move back and forth on the slide rail.
  • the cover plate can move with the servo cylinders on the corresponding side.
  • a load sensor is arranged at the center of the front end of the piston rod of the servo cylinder, and an indenter is installed at the front end of the load sensor after passing through the main casing;
  • At least four evenly distributed acoustic emission meters are installed on the inner wall of each sample pad located at the front, rear, left and right. Put the sample into the cavity surrounded by six sample pads and pass the quick lock After the assembly is installed, the edge sealant at the joint of the sample pad is sealed to form a sample gasket, thereby sealing the sample; the edge sealant is brushed with liquid silicone rubber on the edges that need to be sealed , After the silicone rubber is cured, the sealing between the sample pads can be realized;
  • Step 6 Inject a liquid heat transfer medium into the inner cavity of the main casing
  • Step 7 Water injection test
  • Step 8 Monitoring and analysis of crack growth
  • Step 10 Sort out the test data.
  • the sample is a cube, and the size of the sample is 200 ⁇ 200 ⁇ 200 mm.
  • the diameter of the water injection hole in the raw coal sample is 12 mm and the hole depth is 105 mm; the outer diameter of the water injection pipe is 12 mm and the length is 95 mm.
  • the new true triaxial test test device is adopted. Compared with the traditional cavity structure enclosed by the inner and outer frames, the main body of the test device is only provided with a cast-shaped integral ring frame.
  • the sample spacer block encloses a sample gasket to contain the sample, thereby omitting the separate pressure-resistant cavity formed between the traditional inner and outer layers.
  • the indenter directly touches the sample pad on the corresponding side after passing through the main chassis. On the block, it can free up more space to arrange the overall ring frame with larger size and thickness, so that the cavity can withstand greater pressure and can meet the simulation test of more complex environments;
  • the servo cylinder directly exerts force on each surface of the sample without passing through the pressure chamber.
  • dynamic sealing needs to be considered, thus simplifying the structure and reducing The cost and reliability are higher.
  • the traditional inner frame is thinner than the outer frame, the inner frame is prone to expansion and deformation when the pressure is high, which further affects the sealing between the inner frame and the servo cylinder;
  • Figure 1 is a schematic diagram of the structure of the true triaxial test device used in the present invention (including two states of sample loading and removal).
  • Figure 2 is a left side view of the host and the host supporting assembly in Figure 1;
  • Figure 3 is a perspective view of a sample gasket surrounded by six sample gaskets.
  • Fig. 4 is a front view of the cross-sectional state of Fig. 3.
  • Figure 5 shows the state after the edge seal of the sample pad is cured with silicone rubber.
  • a test method for crack propagation caused by water injection in high temperature coal under true three-dimensional stress including the following steps:
  • Step 2 Drill a water injection hole for the test piece
  • Step three install the water injection pipe
  • the sample is a cube and the size of the sample is 200 ⁇ 200 ⁇ 200mm.
  • the diameter of the water injection hole 15 in the raw coal sample is 12 mm, and the hole depth is 105 mm; the outer diameter of the water injection pipe is 12 mm, and the length is 95 mm.
  • Step 4 The sample is installed on the test device of the true triaxial test
  • the true three-axis test device is mainly composed of the main engine A, the main engine support component B, the slide rail C, the slide rail support component D and the servo cylinder E.
  • the host A is supported on the ground by the host support assembly B, and six sets of servo cylinders E are arranged in the up and down, left and right, and front and rear directions outside the host A (namely, the three directions of XYZ).
  • the slide rail C extends forward and backward below the host A, and the slide rail C passes through the host A and is supported on the ground by the slide rail support assembly D.
  • the integral annular frame 1 is formed by casting.
  • the integral annular frame 1 has holes on the front and rear sides, and a cover plate 2 is provided on the outside of each hole position.
  • the integral ring frame 1 and the two cover plates 2 jointly enclose the main frame.
  • At least two heating rods 17 are symmetrically installed on the upper and lower walls of the main casing at left and right intervals.
  • the inner cavity of the main unit is used to place the sample 3, and the upper, lower, left, right, front and rear sides of the sample 3 are equipped with sample pads 4, a total of six sample pads 4 are required.
  • a sample moving bracket 5 that can move back and forth on the slide rail C is provided under the sample pad 4 on the lower side.
  • the front and rear servo cylinders E are arranged outside the cover plate 2 on the corresponding side, and the front and rear servo cylinders E are equipped with cylinder moving brackets 6 that can move back and forth on the slide rail C.
  • the cover plate 2 can follow the corresponding side Servo cylinder E moves together.
  • the servo cylinders E on the upper, lower, left and right sides are arranged outside the corresponding sides of the integral ring frame.
  • a load sensor 8 is provided at the center of the front end of the piston rod 7 of the servo cylinder E, and the load sensor 8 is preferably embedded in installation.
  • the front end of the load sensor 8 is provided with an indenter 9, and the front end of the load sensor 8 passes through the main casing and is installed with an indenter 9.
  • the indenter 9 directly abuts the sample pad 4 on the corresponding side. Before the test, install the sample spacer 4 outside the sample 3, and then seal the joint of the sample spacer 4.
  • sample moving bracket 5 and the cylinder moving bracket 6 on the rear side are sequentially pushed into the inner cavity of the host and fixed so that all the indenters 9 directly abut the sample pad 4 on the corresponding side before the test.
  • At least four evenly distributed acoustic emission meters 18 are installed on the inner wall of each sample pad 4 located at the front, rear, left, and right.
  • the acoustic emission meters on each sample pad 4 are not limited to four. It can be five or nine.
  • the edge sealant is applied with liquid silicone rubber on the edges that need to be sealed, and the seal between the sample pads 4 can be realized after the silicone rubber is cured (as shown in Figure 5).
  • the pre-sealing is achieved after the silicone rubber is cured.
  • the silicone rubber is tightly attached to the sample through the confining pressure of the inner cavity of the host, which can not only achieve the sealing between the adjacent surfaces of the sample pad 4, but also weaken the edges. The boundary effect at the place.
  • the servo cylinder E is provided with a cylinder displacement sensor 10, the upper, lower, left and right sides of the servo cylinders E are fixedly installed on the integral ring frame 1 through the end cover 11, and the front and rear servo cylinders E are fixedly installed on the integral ring through the cover plate 2.
  • the piston rods 7 are provided with bushings at the positions where the piston rods 7 pass through the main casing to ensure the airtightness of the inner cavity of the main body.
  • the sample deformation displacement sensor 12 is provided in pairs, and the sample deformation displacement sensor 12 is installed on the sample through the extension rod 13 of the displacement sensor. Outside the edge of the cushion block 4, and a pair of sample deformation displacement sensors 12 in the same direction are arranged diagonally staggered, which can realize the measurement of unbalanced and uneven deformation under true triaxial conditions.
  • the control high-pressure valve in the electro-hydraulic servo booster is greater than the pressure of the highest output of the booster, in order to ensure high reliability and long service life.
  • the hydraulic pressure source is also equipped with an axial piston pump hydraulic pressure source, and the hydraulic pressure source has high and low pressure conversion, which is convenient for the smooth switching of high and low pressure during the test.
  • the stress is applied to the sample to a predetermined value through the six indenters at the front, back, left, right, up and down.
  • Step 6 Inject a liquid heat transfer medium into the inner cavity of the main casing
  • Step 7 Water injection test
  • acoustic emission meter 18 inject high-pressure water into the test piece through the water injection hole 15 to make the raw coal hydraulically wet. After reaching the predetermined time, stop the water injection, and record the pressure of the front, back, left, right, upper and lower six pressure heads in the process And parameter information such as displacement change and temperature.
  • Step 8 Monitoring and analysis of crack growth
  • Acoustic emission positioning technology is used to locate the crack damage propagation during the wetting process of the specimen, and analyze the internal crack propagation of the raw coal specimen caused by cold water injection.
  • Step 10 Sort out the test data.
  • the following table shows the recorded data during the test.

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Abstract

本发明公开了一种真三维应力下高温煤体注水润湿致其裂隙扩展的试验方法，包括试样准备；试件钻注水孔；安装注水管；试样在真三轴试验测试装置上安装；施加三轴应力；向主机壳内腔注入液体传热介质；注水试验；裂纹扩展监测分析；同组其它试验；整理试验数据。采用在原煤试件顶部居中位置处钻竖直延伸的注水孔，在主机壳的上、下壁上各左右间隔地对称安装加热棒，在前、后、左、右四个试样垫块的内壁上安装声发射仪，再将试样置于专用的真三轴试验测试装置中，进行真三维应力下高温煤体注水润湿致其裂隙扩展的试验，用于研究注水润湿对煤体降温及其损伤机理，为有效分布注水钻孔，提高经济效益奠定理论基础。

Description

真三维应力下高温煤体注水润湿致其裂隙扩展的试验方法 技术领域
本发明属于煤岩体模拟试验技术领域，具体涉及一种真三维应力下高温煤体注水润湿致其裂隙扩展的试验方法。
背景技术
煤炭是我国的主要能源，我国煤炭开采深度平均每年以8～10m的速度递增，而占当前煤矿1/3的东部矿井开采深度正以平均每年10～25m的速度增加。当矿井深度达到1000m时，矿井中温度升高50％由围岩散热造成。矿井热害问题，已经成为深部矿井开采的主要问题。研究深部矿井煤岩体注水对围岩温度场的影响，对改善井下工人的作业环境具有重要意义。
煤层注水是一种常见的降温方式，它是在回采工作面附近的平巷或斜巷布置钻孔，通过向煤层注水，利用水压将冷水注入即将回采的煤中，具有高效廉价的优势，同时煤层注水还可起到驱替瓦斯与降尘的效果。另外，由于煤体的热胀冷缩特性，当高温问题在冷水降温作用下，其内部由于冷缩产生裂隙，进一步增加了煤体渗透性，促进了冷水润湿范围扩展。
传统的认识和分析高温岩体水力润湿手段主要为数值仿真，其优势是成本低廉，可任意更改边界条件，但是数值仿真计算往往难以反映真实情况。已有成果表明国内外学者已经在该领域进行了一定的室内实验研究。但是，已有试验装置中，多为将装有试件的腔体整体放入水浴或油浴中，或者是在 试件腔体外围缠绕加热装置或者加热层，无法真实还原工程实践中的热传导现象。其次，在传统的煤体润湿试验装置中，多集中于研究其渗流特性，忽略了冷水对煤体造成的裂隙损伤。
发明内容
本发明所要解决的技术问题是提供一种模拟真三轴应力作用下，高温煤体注水润湿致其裂隙扩展的试验方法，用于研究注水润湿对煤体降温及其损伤机理，为有效分布注水钻孔，提高经济效益奠定理论基础。
为此，本发明所采用的技术方案为：一种真三维应力下高温煤体注水润湿致其裂隙扩展的试验方法，包括以下步骤：
步骤一、试样制备；
将原煤块体切割成六面体，然后通过磨床进行加工，使其端面平整度为±0.02mm以内，在105±15°温度下烘干24±4小时后，冷却至常温备用；
步骤二、试件钻注水孔；
用钻机在原煤试件顶部居中位置处钻竖直延伸的注水孔；
步骤三、安装注水管；
选取外径与注水孔直径相等，长度比注水孔深度小8—12mm的注水管，并在注水管外壁均匀涂抹硅橡胶，将注水管插入注水孔内，通过硅橡胶密封注水管外壁与注水孔之间的缝隙，然后在注水孔口部安装万向密封接头；
步骤四、试样在真三轴试验测试装置上安装；
所述真三轴试验测试装置包括主机、主机支撑组件、滑轨、滑轨支撑组件和伺服油缸，六套所述伺服油缸布置在主机外的上下、左右、前后方向，所述滑轨在主机下方前后延伸设置，且穿过主机后通过滑轨支撑组件支撑在 地面上，所述主机包括铸造成型的整体环形框架，所述整体环形框架的前后两侧开孔，并在每个开孔位置外侧配备有盖板，所述整体环形框架和盖板围成主机壳，在主机壳的上、下壁上各左右间隔地对称安装有至少两个加热棒，主机内腔用于放置试样，试样的上、下、左、右、前、后侧外分别配备有试样垫块，位于下侧的所述试样垫块下方设置有能在滑轨上前后移动的试样移动支架；前后侧的伺服油缸下方均设置有能在滑轨上前后移动的油缸移动支架，所述盖板能随着对应侧的伺服油缸一起移动，上下左右侧的伺服油缸固设在整体环形框架的对应侧外，伺服油缸的活塞杆前端居中位置处设置有载荷传感器，所述载荷传感器的前端穿过主机壳后安装有压头；
位于前、后、左、右的每个试样垫块的内壁上安装有至少四个均匀分布的声发射仪，将试样放入六块试样垫块围成的腔体内并通过快锁组合安装后再结合试样垫块接缝处的棱边密封胶密封成一个试样密封垫，从而将试样密封其中；所述棱边密封胶采用在需要密封的棱边刷涂液态硅橡胶，待硅橡胶固化后便能实现试样垫块之间的密封；
首先将试样密封垫安装在下压头上，再控制上压头下移与万向密封接头安装在一起，同时上压头与试样密封垫上表面贴合，最后分别控制前、后、左、右四个压头移动，使对应的压头分别贴合到试样密封垫的对应表面；
步骤五、施加三轴应力；
通过前、后、左、右、上、下六个压头对试样施加应力至预定值；
步骤六、向主机壳内腔注入液体传热介质；
选取液压油作为传热介质注入三轴试验测试装置的主机壳内腔中，开启安装在主机壳内腔中的所有加热棒，加热液压油至预定温度并保持24±4小 时，使得主机壳内腔、六个压头以及试件内部均达到预定温度；
步骤七、注水试验；
打开声发射仪，通过注水孔对试件高压注水使原煤水力润湿，达到预定时间后，停止注水，记录该过程中前、后、左、右、上、下六个压头的压力与位移变化以及温度等参数信息；
步骤八、裂纹扩展监测分析；
利用声发射定位技术，对试件润湿过程中的裂隙损伤扩展进行定位，分析冷水注入引起的原煤试件内部裂纹扩展情况；
步骤九、同组其它试验；
更换原煤试件，改变液体传热介质，或者改变三轴压力、注水速率，重复步骤一至步骤八；
步骤十、整理试验数据。
作为上述方案的优选，所述试样为正方体，试样尺寸为200×200×200mm。
进一步优选为，所述原煤试件中注水孔的孔径为12mm，孔深为105mm；注水管外径为12mm，长度为95mm。
本发明的有益效果：
(1)采用新的真三轴试验测试装置，相比传统的内外层框架围成的腔体结构，本测试装置主机上仅设置铸造成型的整体环形框架，由设置在试样外的六个试样垫块围成一个试样密封垫用于容纳试样，从而省略了传统内外层之间形成的单独的耐压腔体，压头穿过主机壳后直接抵在对应侧的试样垫块上，能腾出更多的空间布置尺寸、厚度更大的整体环形框架，因此使得腔体能承受的压力更大，能满足更复杂环境的模拟测试试验；
(2)由于省略了内层框架，伺服油缸直接施加力于试样各面，不需要穿过耐压腔体，伺服油缸穿过耐压腔体还需要考虑动密封，因此简化了结构，降低了成本，且可靠性更高；同时由于传统的内层框架相比外层框架更薄，压力较大时内层框架易产生膨胀变形，进一步影响内框架与伺服油缸之间的密封性；
(3)本测试装置中压头和试样垫块分离设计，对试样垫块连接处涂液态硅橡胶固化后密封，使得注入流体不会渗到外部区域；
(4)整体环形框架的前后两侧开孔，并在每个开孔位置外侧配备有盖板，共同围成主机壳，对于试样前侧零部件的安装更加方便；而传统结构仅在后侧开孔配备盖板，前侧零部件需要检修或装拆试样，需要通过试样移动支架将试样移出整体环形框架，非常麻烦；
(5)采用在原煤试件顶部居中位置处钻竖直延伸的注水孔，在主机壳的上、下壁上各左右间隔地对称安装加热棒，在前、后、左、右四个试样垫块的内壁上安装声发射仪，再将试样置于专用的真三轴试验测试装置中，进行真三维应力下高温煤体注水润湿致其裂隙扩展的试验，用于研究注水润湿对煤体降温及其损伤机理，为有效分布注水钻孔，提高经济效益奠定理论基础。
附图说明
图1为本发明所采用的真三轴试验测试装置的结构示意图(含试样装入和取出两种状态)。
图2为图1中主机和主机支撑组件的左视图。
图3为六块试样垫块围成的试样密封垫的立体图。
图4为图3的剖视状态的正视图。
图5为试样垫块棱边密封采用硅橡胶固化后的状态。
具体实施方式
下面通过实施例并结合附图，对本发明作进一步说明：
一种真三维应力下高温煤体注水润湿致其裂隙扩展的试验方法，包括以下步骤：
步骤一、试样制备；
将原煤块体切割成六面体，然后通过磨床进行加工，使其端面平整度为±0.02mm以内，在105±15°温度下烘干24±4小时后，冷却至常温备用；
步骤二、试件钻注水孔；
用钻机在原煤试件顶部居中位置处钻竖直延伸的注水孔15(如图4所示)；
步骤三、安装注水管；
选取外径与注水孔15直径相等，长度比注水孔15深度小8—12mm的注水管，并在注水管外壁均匀涂抹硅橡胶，将注水管插入注水孔15内，通过硅橡胶密封注水管外壁与注水孔15之间的缝隙，然后在注水孔15口部安装万向密封接头16。
最好是，试样为正方体，试样尺寸为200×200×200mm。另外，原煤试件中注水孔15的孔径为12mm，孔深为105mm；注水管外径为12mm，长度为95mm。
步骤四、试样在真三轴试验测试装置上安装；
如图1—图4所示，真三轴试验测试装置主要由主机A、主机支撑组件B、滑轨C、滑轨支撑组件D和伺服油缸E组成。主机A通过主机支撑组件B支撑在地面上，六套伺服油缸E布置在主机A外的上下、左右、前后方向(即XYZ 三个方向)。滑轨C在主机A下方前后延伸设置，且滑轨C穿过主机A后通过滑轨支撑组件D支撑在地面上。
整体环形框架1采用铸造成型，整体环形框架1的前后两侧开孔，并在每个开孔位置外侧配备有盖板2。整体环形框架1和两个盖板2共同围成主机壳。在主机壳的上、下壁上各左右间隔地对称安装有至少两个加热棒17。主机内腔用于放置试样3，试样3的上、下、左、右、前、后侧外分别配备有试样垫块4，共需六个试样垫块4。位于下侧的试样垫块4下方设置有能在滑轨C上前后移动的试样移动支架5。
前后侧的伺服油缸E设置在对应侧的盖板2外，且前后侧的伺服油缸E下均设置有能在滑轨C上前后移动的油缸移动支架6，盖板2能随着对应侧的伺服油缸E一起移动。上下左右侧的伺服油缸E设置在整体环形框架对应侧外。
伺服油缸E的活塞杆7前端居中位置处设置有载荷传感器8，载荷传感器8最好采用嵌入安装。载荷传感器8的前端设置有压头9，载荷传感器8的前端穿过主机壳后安装有压头9。对试样3加载时，压头9直接抵在对应侧的试样垫块4上。在进行试验前，将试样垫块4安装在试样3外，再在试样垫块4连接处进行密封，完成密封后，将试样3放置在试样移动支架5上，并将试样移动支架5及后侧的油缸移动支架6依次推入到主机内腔内并固定，使所有压头9均直接抵在对应侧的试样垫块4之后再进行试验。
位于前、后、左、右的每个试样垫块4的内壁上安装有至少四个均匀分布的声发射仪18，每个试样垫块4上的声发射仪不限于四个，也可以是五个或九个不等。
将试样放入六块试样垫块4围成的腔体内并通过快锁14组合安装后，再结合试样垫块4接缝处的棱边密封胶密封成一个试样密封垫，从而将试样3密封其中；棱边密封胶采用在需要密封的棱边刷涂液态硅橡胶，待硅橡胶固化后便能实现试样垫块4之间的密封(如图5所示)。在硅橡胶固化后实现预密封，在试验时，通过主机内腔的围压，使硅橡胶紧贴试样，不仅能实现试样垫块4相邻表面之间的密封，还能减弱棱边处的边界效应。最好是，伺服油缸E内设置有油缸位移传感器10，上下左右侧的伺服油缸E通过端盖11固定安装在整体环形框架1上，前后侧的伺服油缸E通过盖板2固定安装在整体环形框架1上，所有活塞杆7穿过主机壳的位置处均设置有衬套，以保证主机内腔的密封性。
最好是，在六个试样垫块4围成的密封腔外的XYZ方向上，成对配备有试样变形位移传感器12，试样变形位移传感器12通过位移传感器加长杆13安装在试样垫块4的棱边外，且同一方向上的一对试样变形位移传感器12呈对角错开设置，能实现真三轴条件下不平衡不均匀变形的测量。
最好是，还配备有两套电液伺服增压器，分别为主机内腔提供围压、为试样提供注水压或渗透压，让围压、注水压或渗透压分别控制，可完成复杂的试验条件。电液伺服增压器内的控制高压阀门的工作压力大于增压最高输出的压力，为了保证工作的高可靠性和长使用寿命。
最好是，还配备有轴向柱塞泵液压源，且液压源带高低压转换，便于试验时，高低压的顺利切换。
先将试样装入六块试样垫块4围成的试样密封垫内，再在棱边刷涂液态硅橡胶，待硅橡胶固化后，通过试样移动支架5将试样推入到主机内腔中， 最后通过油缸移动支架6将前后侧的盖板2安装在整体环形框架1上，安装时保证主机内腔的密封，之后开始试验。
首先将试样密封垫安装在下压头上，再控制上压头下移与万向密封接头16安装在一起，同时上压头与试样密封垫上表面贴合，最后分别控制前、后、左、右四个压头移动，使对应的压头分别贴合到试样密封垫的对应表面。
步骤五、施加三轴应力；
通过前、后、左、右、上、下六个压头对试样施加应力至预定值。
步骤六、向主机壳内腔注入液体传热介质；
选取液压油作为传热介质注入三轴试验测试装置的主机壳内腔中，开启安装在主机壳内腔中的所有加热棒17，加热液压油至预定温度并保持24±4小时，使得主机壳内腔、六个压头以及试件内部均达到预定温度。
步骤七、注水试验；
打开声发射仪18，通过注水孔15对试件高压注水使原煤水力润湿，达到预定时间后，停止注水，记录该过程中前、后、左、右、上、下六个压头的压力与位移变化以及温度等参数信息。
步骤八、裂纹扩展监测分析；
利用声发射定位技术，对试件润湿过程中的裂隙损伤扩展进行定位，分析冷水注入引起的原煤试件内部裂纹扩展情况。
步骤九、同组其它试验；
更换原煤试件，改变液体传热介质，或者改变三轴压力、注水速率，重复步骤一至步骤八。
步骤十、整理试验数据。下表为试验过程中的记录数据。
Figure PCTCN2020079420-appb-000001

Claims (3)

  1. 一种真三维应力下高温煤体注水润湿致其裂隙扩展的试验方法，其特征在于，包括以下步骤：
    步骤一、试样制备；
    将原煤块体切割成六面体，然后通过磨床进行加工，使其端面平整度为±0.02mm以内，在105±15°温度下烘干24±4小时后，冷却至常温备用；
    步骤二、试件钻注水孔；
    用钻机在原煤试件顶部居中位置处钻竖直延伸的注水孔(15)；
    步骤三、安装注水管；
    选取外径与注水孔(15)直径相等，长度比注水孔(15)深度小8—12mm的注水管，并在注水管外壁均匀涂抹硅橡胶，将注水管插入注水孔(15)内，通过硅橡胶密封注水管外壁与注水孔(15)之间的缝隙，然后在注水孔(15)口部安装万向密封接头(16)；
    步骤四、试样在真三轴试验测试装置上安装；
    所述真三轴试验测试装置包括主机(A)、主机支撑组件(B)、滑轨(C)、滑轨支撑组件(D)和伺服油缸(E)，六套所述伺服油缸(E)布置在主机(A)外的上下、左右、前后方向，所述滑轨(C)在主机(A)下方前后延伸设置，且穿过主机(A)后通过滑轨支撑组件(D)支撑在地面上，所述主机(A)包括铸造成型的整体环形框架(1)，所述整体环形框架(1)的前后两侧开孔，并在每个开孔位置外侧配备有盖板(2)，所述整体环形框架(1)和盖板(2)围成主机壳，在主机壳的上、下壁上各左右间隔地对称安装有至少两个加热 棒(17)，主机内腔用于放置试样(3)，试样(3)的上、下、左、右、前、后侧外分别配备有试样垫块(4)，位于下侧的所述试样垫块(4)下方设置有能在滑轨(C)上前后移动的试样移动支架(5)；前后侧的伺服油缸(E)下方均设置有能在滑轨(C)上前后移动的油缸移动支架(6)，所述盖板(2)能随着对应侧的伺服油缸(E)一起移动，上下左右侧的伺服油缸(E)固设在整体环形框架(1)的对应侧外，伺服油缸(E)的活塞杆(7)前端居中位置处设置有载荷传感器(8)，所述载荷传感器(8)的前端穿过主机壳后安装有压头(9)；
    位于前、后、左、右的每个试样垫块(4)的内壁上安装有至少四个均匀分布的声发射仪(18)，将试样放入六块试样垫块(4)围成的腔体内并通过快锁(14)组合安装后再结合试样垫块(4)接缝处的棱边密封胶密封成一个试样密封垫，从而将试样(3)密封其中；所述棱边密封胶采用在需要密封的棱边刷涂液态硅橡胶，待硅橡胶固化后便能实现试样垫块(4)之间的密封；
    首先将试样密封垫安装在下压头上，再控制上压头下移与万向密封接头(16)安装在一起，同时上压头与试样密封垫上表面贴合，最后分别控制前、后、左、右四个压头移动，使对应的压头分别贴合到试样密封垫的对应表面；
    步骤五、施加三轴应力；
    通过前、后、左、右、上、下六个压头对试样施加应力至预定值；
    步骤六、向主机壳内腔注入液体传热介质；
    选取液压油作为传热介质注入三轴试验测试装置的主机壳内腔中，开启安装在主机壳内腔中的所有加热棒(17)，加热液压油至预定温度并保持24±4小时，使得主机壳内腔、六个压头以及试件内部均达到预定温度；
    步骤七、注水试验；
    打开声发射仪(18)，通过注水孔(15)对试件高压注水使原煤水力润湿，达到预定时间后，停止注水，记录该过程中前、后、左、右、上、下六个压头的压力与位移变化以及温度等参数信息；
    步骤八、裂纹扩展监测分析；
    利用声发射定位技术，对试件润湿过程中的裂隙损伤扩展进行定位，分析冷水注入引起的原煤试件内部裂纹扩展情况；
    步骤九、同组其它试验；
    更换原煤试件，改变液体传热介质，或者改变三轴压力、注水速率，重复步骤一至步骤八；
    步骤十、整理试验数据。
  2. 按照权利要求1所述的真三维应力下高温煤体注水润湿致其裂隙扩展的试验方法，其特征在于：所述试样为正方体，试样尺寸为200×200×200mm。
  3. 按照权利要求2所述的真三维应力下高温煤体注水润湿致其裂隙扩展的试验方法，其特征在于：所述原煤试件中注水孔(15)的孔径为12mm，孔深为105mm；注水管外径为12mm，长度为95mm。
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CN114137012B (zh) * 2021-10-29 2022-11-15 合肥综合性国家科学中心能源研究院(安徽省能源实验室) 一种真三轴实验磁信号捕集装置及应用方法
CN114397369A (zh) * 2021-12-31 2022-04-26 临沂大学 一种用于混凝土损伤监测的可埋入多维声发射传感器
CN114397369B (zh) * 2021-12-31 2023-12-22 临沂大学 一种用于混凝土损伤监测的可埋入多维声发射传感器
CN114894566A (zh) * 2022-04-07 2022-08-12 中国矿业大学 渗流-冻融循环作用微生物固化试样制备装置及试验方法
CN114894566B (zh) * 2022-04-07 2024-05-07 中国矿业大学 渗流-冻融循环作用微生物固化试样制备装置及试验方法
CN115977621A (zh) * 2022-12-23 2023-04-18 重庆大学 Vhsd直井水平井水力连通开采稠油藏的物理模拟方法
CN116717221A (zh) * 2023-08-08 2023-09-08 中国煤炭地质总局勘查研究总院 模拟微生物与二氧化碳联合增产煤层气的实验装置
CN116717221B (zh) * 2023-08-08 2023-10-24 中国煤炭地质总局勘查研究总院 模拟微生物与二氧化碳联合增产煤层气的实验装置

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