CN112362813B - Root system drawing test system and method based on PIV technology - Google Patents
Root system drawing test system and method based on PIV technology Download PDFInfo
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Abstract
本发明公开了一种基于PIV技术的根系拉拔试验系统及方法,该系统包括压力室、围压控制装置、吸力控制装置、根系拉拔装置、PIV测试装置,压力室整体为半圆柱体状密封结构,其侧面呈透明状,且压力室内放置有半圆柱体状的试样,试样的竖直侧面内包含一条沿竖直方向从中心劈开的植物根系;围压控制装置与压力室双向连通进行围压调节,吸力控制装置与压力室双向连通进行基质吸力调节,根系拉拔装置设置于试样的上方,PIV测试装置位于压力室呈透明状的侧面正前方,测定土粒和植物根系的运动轨迹和速率。该方法采用基于PIV技术的根系拉拔试验系统,实现不同围压和基质吸力作用下含根系土中不同龄期根系的抗拉拔特性参数。
The invention discloses a root system pulling test system and method based on PIV technology. The system includes a pressure chamber, a confining pressure control device, a suction force control device, a root system pulling device and a PIV test device. The whole pressure chamber is in the shape of a semi-cylindrical body. Sealed structure, its side is transparent, and a semi-cylindrical sample is placed in the pressure chamber, and the vertical side of the sample contains a plant root system split from the center along the vertical direction; confining pressure control device and pressure chamber Two-way communication is used to adjust the confining pressure, the suction control device is connected to the pressure chamber to adjust the substrate suction, the root pulling device is set above the sample, and the PIV test device is located directly in front of the transparent side of the pressure chamber to measure soil particles and plants. Root trajectory and velocity. The method adopts the root pull-out test system based on PIV technology to realize the pull-out characteristic parameters of roots of different ages in root-containing soil under the action of different confining pressures and matrix suction.
Description
技术领域technical field
本发明属于土木工程行业的土工试验设备领域,涉及一种基于PIV技术的根系拉拔试验系统及方法。The invention belongs to the field of geotechnical test equipment in the civil engineering industry, and relates to a root system pulling test system and method based on PIV technology.
背景技术Background technique
近年来,我国道路和铁道等交通基础设施建设不断取得突破,在全国各地形成了不计其数的人工边坡,其有效防护是当前地质灾害防治的重要内容。植物生态防护作为一种可显著提高浅层土体强度的措施,被广泛应用于土质边坡防护,其机理主要在于植物根系的力学固土效应。植物根系在土中盘根错节,与土体共同构成根土复合材料,当土体在外力作用下发生变形时,根系的张拉会限制土体的变形,从而提高土体抗剪强度。在实际工程中,当边坡浅层土体发生滑动时,部分根系因达到抗拉强度而被拉断,还有部分未被拉断而是被拔出引起周围土体松动,这些都将显著降低土体强度和边坡稳定性。因此,研究植物根系的抗拉拔特性具有重要意义。In recent years, my country has made breakthroughs in the construction of transportation infrastructure such as roads and railways, and countless artificial slopes have been formed all over the country. Its effective protection is an important part of the current geological disaster prevention and control. As a measure that can significantly improve the strength of shallow soil, plant ecological protection is widely used in soil slope protection, and its mechanism is mainly due to the mechanical soil-fixing effect of plant roots. Plant roots are intertwined in the soil, and together with the soil, they form a root-soil composite material. When the soil is deformed under the action of external force, the tension of the root system will limit the deformation of the soil, thereby improving the shear strength of the soil. In practical engineering, when the shallow soil of the slope slides, some of the roots are broken due to reaching the tensile strength, and some are pulled out instead of being broken, causing the surrounding soil to loosen. Reduce soil strength and slope stability. Therefore, it is of great significance to study the anti-pulling properties of plant roots.
目前,虽然已有文献报道了一些植物的单根抗拉拔性能,但较少分析根系与土体共同作用时根系的抗拉拔特性,且很少分析根系被拉断或拔出时对附近土层的扰动程度及范围,究其原因主要是缺乏用于开展这方面研究的仪器设备。现有试验方法如单根拉拔试验和直剪试验在测定植物根系抗拉拔特性时存在诸多难点和问题,主要包括:At present, although the single root pullout resistance of some plants has been reported in the literature, the pullout resistance of the root system when the root system interacts with the soil is rarely analyzed, and the damage to nearby roots when the root system is broken or pulled out is rarely analyzed. The degree and scope of soil disturbance is mainly due to the lack of instruments and equipment for carrying out research in this area. Existing test methods such as single root pull test and direct shear test have many difficulties and problems in determining the pull-out resistance of plant roots, mainly including:
1.含根系土几乎都是非饱和的,且植物生长会吸收土中水分,从而减小土体孔隙水压力、增加基质吸力。基质吸力的存在将显著改变土体的强度和变形特性,使之与常规饱和土体性质截然不同。相应地,根土界面特性也会发生明显变化。但现有仪器在测定根系的抗拉拔特性时无法考虑基质吸力的影响。1. Almost all root-containing soils are unsaturated, and plant growth will absorb water in the soil, thereby reducing soil pore water pressure and increasing matrix suction. The existence of matrix suction will significantly change the strength and deformation characteristics of soil, making it completely different from conventional saturated soil. Correspondingly, the properties of the root-soil interface also changed significantly. However, existing instruments cannot consider the influence of substrate suction when measuring the pullout resistance of roots.
2.由于所处自然环境各异,土体所承受的围压大小不同,导致土体的松紧程度不同,故植物根系与土体之间的相互作用力也随之不同。显然,这将进一步影响植物根系的抗拉拔性能。然而,现有仪器在进行抗拉拔试验时还无法精确控制土体的围压大小,故无法考虑围压对根系拉拔特性的影响。2. Due to the different natural environment, the confining pressure of the soil body is different, resulting in different degree of tightness of the soil body, so the interaction force between the plant root system and the soil body is also different. Obviously, this will further affect the pull-out resistance of plant roots. However, the existing instruments cannot precisely control the confining pressure of the soil when conducting the pullout test, so the influence of the confining pressure on the pullout characteristics of the root system cannot be considered.
3.路基边坡采用植物生态防护时,在极端情况下,如果边坡浅层土体在外荷载作用下发生滑动,许多植物根系将被向坡体外侧拔出,这不可避免地会对周围土体产生扰动,从而影响边坡深层土体的稳定性。但现有仪器尚无法准确测定植物根系在土体中的滑移变形及其对周围土体的扰动程度和范围。3. When the subgrade slope is protected by plants, in extreme cases, if the shallow soil of the slope slides under the action of external loads, many plant roots will be pulled out to the outside of the slope, which will inevitably affect the surrounding soil. Therefore, the stability of the deep soil mass of the slope is affected. However, the existing instruments cannot accurately measure the slip deformation of plant roots in the soil and the degree and scope of disturbance to the surrounding soil.
综上所述,为了准确测定不同围压和基质吸力作用下含根系土中不同龄期单根的抗拉拔特性(抗拉强度、抗拔力和根土界面摩擦系数)和不同龄期根系的抗拉拔特性(主根抗拉强度和根系抗拔力),并分析拉拔过程中土体、植物单根或根系的变形和运动轨迹,探讨单根或根系滑移对土体的扰动范围,揭示相关机理,研发一种新型植物根系拉拔试验系统是十分有必要的。In summary, in order to accurately determine the pull-out characteristics (tensile strength, pull-out resistance and root-soil interface friction coefficient) of a single root at different ages in root-containing soil under different confining pressures and matrix suction, and root systems at different ages The pull-out characteristics (tensile strength of main root and root pull-out resistance) are analyzed, and the deformation and movement trajectory of soil, single root or root system of soil, single root or root system during the pulling process are analyzed, and the disturbance range of soil mass caused by single root or root system slip is discussed. , revealing the relevant mechanism, it is very necessary to develop a new type of plant root pulling test system.
发明内容SUMMARY OF THE INVENTION
本发明实施例的目的在于提供一种基于PIV技术的根系拉拔试验系统及方法,以解决现有仪器在测定根系的抗拉拔特性时无法考虑基质吸力、围压对根系拉拔特性的影响的问题,以及现有仪器无法准确测定植物根系在土体中的滑移变形及其对周围土体的扰动程度和范围的问题。The purpose of the embodiments of the present invention is to provide a root pulling test system and method based on PIV technology, so as to solve the problem that the existing instruments cannot consider the influence of matrix suction and confining pressure on the root pulling characteristics when measuring the anti-pulling characteristics of roots. However, existing instruments cannot accurately measure the slip deformation of plant roots in the soil and the degree and scope of disturbance to the surrounding soil.
本发明实施例所采用的技术方案是:基于PIV技术的根系拉拔试验系统,包括压力室、围压控制装置、吸力控制装置、根系拉拔装置、PIV测试装置和数据采集系统;压力室整体为半圆柱体状密封结构,其侧面呈透明状,且压力室内放置有半圆柱体状的试样,试样的竖直侧面内包含一条沿竖直方向从中心劈开的植物根系,且植物根系顶端露出于试样顶部;所述围压控制装置与压力室双向连通,对压力室内的试样进行围压调节;所述吸力控制装置与压力室双向连通,对压力室内的试样进行基质吸力调节;所述根系拉拔装置设置于试样的上方,对植物根系施加拉拔力;所述PIV测试装置设置于压力室呈透明状的侧面正前方,对土粒和植物根系的运动轨迹和速率进行测定、记录;所述数据采集系统与围压控制装置、吸力控制装置、PIV测试装置双向电性连接,并与根系拉拔装置的信号输出端电性连接;The technical solution adopted in the embodiment of the present invention is: a root system pulling test system based on PIV technology, including a pressure chamber, a confining pressure control device, a suction control device, a root system pulling device, a PIV test device and a data acquisition system; the overall pressure chamber It is a semi-cylindrical sealing structure, the side of which is transparent, and a semi-cylindrical sample is placed in the pressure chamber. The vertical side of the sample contains a plant root system that is split from the center in the vertical direction. The top of the root system is exposed on the top of the sample; the confining pressure control device is in two-way communication with the pressure chamber to adjust the confining pressure of the sample in the pressure chamber; the suction control device is in two-way communication with the pressure chamber to perform matrix control on the sample in the pressure chamber. Suction adjustment; the root system pulling device is arranged above the sample to exert pulling force on the plant root system; the PIV testing device is arranged in front of the transparent side of the pressure chamber, and the movement trajectory of soil particles and plant roots is affected. and the rate are measured and recorded; the data acquisition system is electrically connected to the confining pressure control device, the suction control device, and the PIV test device in both directions, and is electrically connected to the signal output end of the root pulling device;
所述压力室包括钢制底板、有机玻璃侧壁和钢制顶盖,钢制顶盖、有机玻璃侧壁、钢制底板从上到下依次固定连接形成半圆柱体状密封空间,试样位于半圆柱体状密封空间内,且有机玻璃侧壁竖直设置于试样的侧面外围,有机玻璃侧壁顶部与钢制顶盖的底面密封连接,有机玻璃侧壁底部与钢制底板的顶面密封连接;The pressure chamber includes a steel bottom plate, a plexiglass side wall, and a steel top cover. The steel top cover, the plexiglass side wall, and the steel bottom plate are sequentially connected from top to bottom to form a semi-cylindrical sealed space. Inside the semi-cylindrical sealed space, and the plexiglass sidewall is vertically arranged on the side periphery of the sample, the top of the plexiglass sidewall is sealed with the bottom surface of the steel top cover, and the bottom of the plexiglass sidewall is connected to the top surface of the steel bottom plate. sealed connection;
所述钢制底板的上表面中间区域设有漏斗型的排水槽,排水槽顶部固定有陶土板,试样放置在陶土板上;The middle area of the upper surface of the steel base plate is provided with a funnel-shaped drainage groove, a terracotta plate is fixed on the top of the drainage groove, and the sample is placed on the terracotta plate;
所述钢制底板一侧设有带进出水管阀门的进出水管接口、带围压水管阀门的围压水管接口和带反压水管阀门的反压水管接口,进出水管接口和围压水管接口的一端与压力室内部连通,进出水管接口和围压水管接口的另一端与围压控制装置连通;反压水管接口的一端与排水槽底部连通,反压水管接口的另一端与吸力控制装置连通。One side of the steel base plate is provided with a water inlet and outlet pipe interface with water inlet and outlet pipe valves, a confining pressure water pipe interface with a confining pressure water pipe valve and a back pressure water pipe interface with a back pressure water pipe valve, and one end of the water inlet and outlet pipe interface and the confining pressure water pipe interface It is communicated with the interior of the pressure chamber, and the other end of the inlet and outlet water pipe interface and the confining pressure water pipe interface is communicated with the confining pressure control device;
进一步的,所述压力室顶部即钢制顶盖上设置有与压力室内部、试样外围连通的排气孔,排气孔内设有与其螺纹连接的排气螺丝;所述试样的曲状侧面包裹有将其密封的乳胶膜;Further, the top of the pressure chamber, that is, the steel top cover, is provided with an exhaust hole communicating with the interior of the pressure chamber and the periphery of the sample, and the exhaust hole is provided with an exhaust screw threadedly connected with it; the curve of the sample is provided. The side is wrapped with a latex film that seals it;
所述围压控制装置包括围压水管、围压控制器、进出水管、水缸和水泵,水泵位于水缸内,且水泵通过进出水管与压力室的进出水管接口连通,围压控制器通过围压水管与压力室的围压水管接口连通;The confining pressure control device includes a confining pressure water pipe, a confining pressure controller, an inlet and outlet water pipe, a water tank and a water pump. The pressure water pipe is communicated with the confining pressure water pipe interface of the pressure chamber;
所述围压控制器与数据采集系统双向连通。The confining pressure controller is in bidirectional communication with the data acquisition system.
进一步的,所述压力室顶部即钢制顶盖上设置有与压力室内部连通的进气管接口,且进气管接口设置于试样上方;Further, the top of the pressure chamber, that is, the steel top cover, is provided with an air inlet pipe interface communicating with the interior of the pressure chamber, and the air inlet pipe interface is arranged above the sample;
所述吸力控制装置包括反压控制器、空气压缩机、过滤器、干燥器、气压控制器、安全罐、反压水管和进气管,反压控制器通过反压水管与压力室的反压水管接口相连,进气管一端与压力室顶部的进气管接口连接,其另一端依次经安全罐、气压控制器、干燥器、过滤器与空气压缩机连接;The suction control device includes a back pressure controller, an air compressor, a filter, a dryer, an air pressure controller, a safety tank, a back pressure water pipe and an air intake pipe. The back pressure controller passes through the back pressure water pipe and the back pressure water pipe of the pressure chamber. The interface is connected, one end of the intake pipe is connected to the interface of the intake pipe at the top of the pressure chamber, and the other end is connected to the air compressor through the safety tank, the air pressure controller, the dryer and the filter in turn;
所述反压控制器、气压控制器分别与数据采集系统双向连通。The back pressure controller and the air pressure controller are respectively in bidirectional communication with the data acquisition system.
进一步的,所述钢制顶盖上设有与试样上下对应的凸腔,凸腔顶部留有用于根系拉拔装置的下端伸出的孔洞,孔洞周围设第二密封圈;所述试样上设置有多个依次嵌套的多孔环形垫块,多孔环形垫块和钢制顶盖之间设置有金属垫片;Further, the steel top cover is provided with a convex cavity corresponding to the upper and lower sides of the sample, the top of the convex cavity is provided with a hole for the lower end of the root pulling device to protrude, and a second sealing ring is arranged around the hole; the sample A plurality of porous annular spacers nested in sequence are arranged on the upper part, and a metal gasket is arranged between the porous annular spacer and the steel top cover;
所述根系拉拔装置包括水平夹持装置和竖向拉拔装置,竖向拉拔装置下端经钢制顶盖的凸腔顶部的孔洞伸入压力室内,水平夹持装置设置于钢制顶盖的凸腔内,且水平夹持装置固定在竖向拉拔装置下端,竖向拉拔装置可带动水平夹持装置在压力室内竖直向下移动。The root system pulling device includes a horizontal clamping device and a vertical pulling device. The lower end of the vertical pulling device extends into the pressure chamber through the hole at the top of the convex cavity of the steel top cover, and the horizontal clamping device is arranged on the steel top cover. The horizontal clamping device is fixed on the lower end of the vertical pulling device, and the vertical pulling device can drive the horizontal clamping device to move vertically downward in the pressure chamber.
进一步的,所述竖向拉拔装置包括拉力机、横梁、支架、底座和拉拔杆,底座与横梁通过支架固定连接,压力室固定于底座上,拉力机的伸缩杆设置于横梁上;拉拔杆顶部穿过横梁与拉力机的伸缩杆底端固定连接,拉拔杆的底部经钢制顶盖的凸腔顶部的孔洞伸入压力室内与水平夹持装置连接;拉力机的伸缩杆与拉拔杆之间固定有拉力传感器,横梁底部竖直固定有位移传感器;拉拔杆由夹持装置固定杆和拉拔伸缩杆组成,拉拔伸缩杆顶部与夹持装置固定杆底部可拆卸连接;拉拔伸缩杆上套接固定有位移测杆,位移传感器的指针头接触位移测杆;Further, the vertical pulling device includes a pulling machine, a beam, a bracket, a base and a pulling rod, the base and the beam are fixedly connected through the bracket, the pressure chamber is fixed on the base, and the telescopic rod of the pulling machine is arranged on the beam; The top of the pulling rod passes through the beam and is fixedly connected with the bottom end of the telescopic rod of the tensile machine. The bottom of the pulling rod extends into the pressure chamber through the hole at the top of the convex cavity of the steel top cover and is connected with the horizontal clamping device; the telescopic rod of the tensile machine is connected to the horizontal clamping device. A tension sensor is fixed between the pulling rods, and a displacement sensor is vertically fixed at the bottom of the beam; the pulling rod is composed of a clamping device fixing rod and a pulling telescopic rod, and the top of the pulling extension rod is detachably connected to the bottom of the clamping device fixing rod ;A displacement measuring rod is fixed on the pull-out telescopic rod, and the pointer head of the displacement sensor contacts the displacement measuring rod;
所述水平夹持装置包括电机、螺纹旋杆、连接杆、橡胶垫、夹片、夹片固定杆和水平力传感器,电机为双向同步电机,电机的两个输出轴分别连接一个螺纹旋杆,每个螺纹旋杆上螺纹连接有螺母座,每个螺母座底部经连接杆固定连接水平放置的夹片固定杆,两个夹片固定杆的一端端部相向设置,且两个夹片固定杆相互靠近的一端分别活动连接有夹片,夹片固定杆在螺纹旋杆的带动下可沿夹片内部滑动,且夹片固定杆在夹片内部滑动至尽头后会在螺纹旋杆的作用下带动夹片一起向靠近或远离植物根系的方向移动;夹片内部固定有水平力传感器,夹片固定杆位于夹片内部的一端端部与嵌入夹片内的水平力传感器接触;夹片与植物根系接触面紧贴橡胶垫;The horizontal clamping device includes a motor, a threaded rod, a connecting rod, a rubber pad, a clip, a clip fixing rod and a horizontal force sensor, the motor is a bidirectional synchronous motor, and two output shafts of the motor are respectively connected with a threaded rod, Each threaded rod is threadedly connected with a nut seat, and the bottom of each nut seat is fixedly connected to a horizontally placed clip fixing rod through a connecting rod. The ends close to each other are movably connected with clips, and the clip fixing rod can slide along the inside of the clip under the driving of the threaded rod, and the clip fixing rod will slide to the end inside the clip and will be under the action of the threaded rod. Drive the clips to move together toward or away from the root system of the plant; a horizontal force sensor is fixed inside the clip, and one end of the clip fixing rod inside the clip is in contact with the horizontal force sensor embedded in the clip; the clip is connected to the plant The root contact surface is close to the rubber pad;
所述拉拔伸缩杆下端与电机可拆卸连接,将水平夹持装置固定在竖向拉拔装置下端;The lower end of the pulling telescopic rod is detachably connected with the motor, and the horizontal clamping device is fixed on the lower end of the vertical pulling device;
所述水平力传感器、拉力传感器和位移传感器的信号输出端均与数据采集系统电性连接。The signal output ends of the horizontal force sensor, the tensile force sensor and the displacement sensor are all electrically connected with the data acquisition system.
进一步的,所述PIV测试装置包括矩形测试腔、同步器、激光电源、激光器、激光头、CCD相机、LED灯和PIV连接线,矩形测试腔与压力室均固定于根系拉拔装置的竖向拉拔装置的底座上,矩形测试腔位于压力室正前方,且矩形测试腔是由矩形钢制顶板、矩形钢制底板、三面矩形钢制侧壁以及压力室呈透明状的侧面共同形成的密闭空间;激光头安装在压力室呈透明状的侧面前方下部,激光头与激光器的输出端电性连接,激光电源与激光器的电源端电性连接;矩形测试腔上与压力室呈透明状的侧面相对设置的钢制侧壁内部中心位置固定有CCD相机,同步器连接CCD相机与激光电源,同步器通过PIV连接线与数据采集系统的计算机双向连接;以CCD相机为中心,在其四周的四个方向上各设置一个LED灯;Further, the PIV test device includes a rectangular test cavity, a synchronizer, a laser power supply, a laser, a laser head, a CCD camera, an LED lamp and a PIV connecting line, and the rectangular test cavity and the pressure chamber are fixed in the vertical direction of the root system pulling device. On the base of the drawing device, the rectangular test chamber is located directly in front of the pressure chamber, and the rectangular test chamber is formed by a rectangular steel top plate, a rectangular steel bottom plate, three rectangular steel side walls and the transparent sides of the pressure chamber. Space; the laser head is installed in the lower part of the transparent side of the pressure chamber, the laser head is electrically connected to the output end of the laser, and the laser power supply is electrically connected to the power supply end of the laser; the transparent side of the rectangular test cavity is connected to the pressure chamber A CCD camera is fixed at the inner center of the oppositely arranged steel side wall. The synchronizer is connected to the CCD camera and the laser power supply. The synchronizer is bidirectionally connected to the computer of the data acquisition system through the PIV cable; One LED light is set in each direction;
所述数据采集系统包括计算机和数据采集箱;数据采集箱的输入端分别与围压控制装置的围压控制器,吸力控制装置的反压控制器、气压控制器,以及根系拉拔装置的水平力传感器、拉力传感器、位移传感器的信号输出端电性连接,数据采集箱的输出端以及围压控制器、反压控制器、气压控制器的信号输入端均与计算机电性连接;所述PIV测试装置的CCD相机与计算机双向连接。The data acquisition system includes a computer and a data acquisition box; the input end of the data acquisition box is respectively connected to the confining pressure controller of the confining pressure control device, the back pressure controller and the air pressure controller of the suction control device, and the level of the root pulling device. The signal output ends of the force sensor, tension sensor and displacement sensor are electrically connected, and the output end of the data acquisition box and the signal input ends of the confining pressure controller, the back pressure controller and the air pressure controller are all electrically connected to the computer; the PIV The CCD camera of the test device is bidirectionally connected to the computer.
进一步的,所述有机玻璃侧壁由曲板有机玻璃侧壁和平板有机玻璃侧壁密封连接形成,其中,曲板有机玻璃侧壁设置在试样的曲状侧面外围,平板有机玻璃侧壁设置在试样的竖直侧面正前方,曲板有机玻璃侧壁和平板有机玻璃侧壁分别与钢制底板的顶面以及钢制顶盖的底面密封连接;Further, the plexiglass side wall is formed by sealing the curved plexiglass side wall and the flat plexiglass side wall, wherein the curved plexiglass side wall is arranged on the periphery of the curved side of the sample, and the flat plexiglass side wall is arranged Directly in front of the vertical side of the sample, the curved plexiglass side wall and the flat plexiglass side wall are respectively sealed with the top surface of the steel bottom plate and the bottom surface of the steel top cover;
所述乳胶膜在平展开时为长方形,其宽度与试样的高度相同,其长度大于试样的曲状侧面底部边长;包裹试样的乳胶膜两侧多出来的部分沿平板有机玻璃侧壁向远离试样的方向展开,并通过有机玻璃固定板固定压实在平板有机玻璃侧壁上,使乳胶膜密封住试样;有机玻璃固定板位于钢制底板和钢制顶盖之间并与钢制底板以及钢制顶盖可拆卸连接;The latex film is rectangular when it is flattened, its width is the same as the height of the sample, and its length is greater than the length of the bottom side of the curved side of the sample; the extra part on both sides of the latex film wrapping the sample is along the side of the flat plexiglass. The wall is unfolded away from the sample, and is fixed and compacted on the side wall of the flat plexiglass by the plexiglass fixing plate, so that the latex film seals the sample; the plexiglass fixing plate is located between the steel bottom plate and the steel top cover and is Removable connection with steel bottom plate and steel top cover;
所述曲板有机玻璃侧壁的外围设置有多个支撑管,钢制顶盖和支撑管上均设置有竖直贯穿其的预留孔,钢制底板顶面设置有与钢制顶盖上的预留孔一一对应的螺纹孔,钢制顶盖和钢制底板通过螺杆连接,螺杆从上到下依次穿过钢制顶盖、支撑管上的预留孔后与钢制底板上的螺纹孔螺纹连接。A plurality of support pipes are arranged on the periphery of the side walls of the curved plexiglass, the steel top cover and the support pipes are provided with reserved holes vertically passing through them, and the top surface of the steel bottom plate is provided with a steel top cover. The reserved holes correspond to the threaded holes one by one. The steel top cover and the steel bottom plate are connected by screws. The screws pass through the steel top cover and the reserved holes on the support tube from top to bottom in turn and connect with the steel bottom plate. Threaded hole screw connection.
本发明实施例所采用的另一技术方案是:基于PIV技术的根系拉拔试验方法,采用所述的基于PIV技术的根系拉拔试验系统,按照以下步骤进行:Another technical scheme adopted in the embodiment of the present invention is: the root system pulling test method based on PIV technology, adopts the described root system pulling test system based on PIV technology, and carries out according to the following steps:
步骤S1、试样准备:在试验箱内先铺设50~60mm厚的试验用土,将待测植物种子放入试验箱中心位置,再用试验土填满试验箱,然后定期浇水培育;待植物生长至试验所需程度时,去除土表以上植物花、茎、叶,仅保留根系,再采用圆柱形模具以根系为中心取样;脱模后将圆柱体试样沿根系中心竖向切割成半圆柱体,制备得到试验所需的含根系的试样;Step S1, sample preparation: first lay 50~60mm thick test soil in the test box, put the plant seeds to be tested into the center of the test box, then fill the test box with the test soil, and then water regularly to cultivate; When the growth reaches the level required for the test, remove the flowers, stems, and leaves of the plants above the soil surface, and keep only the root system, and then use a cylindrical mold to take the root system as the center; after demoulding, cut the cylindrical sample vertically along the center of the root system into half. Cylinder, prepare the sample containing root system required for the test;
步骤S2、试样安装:用脱气蒸馏水对压力室的钢制底板上的陶土板进行完全饱和,再将含根系的试样放入压力室内,使其竖直侧面与压力室呈透明状的侧面相接触;然后在试样侧面包裹乳胶膜,使乳胶膜密封住试样;接着在试样上部放置合适数量的多孔环形垫块,控制根系拉拔过程中试样顶部隆起面积;再在多孔环形垫块上放置金属垫片,并使待测的植物根系从多孔环形垫块与金属垫片的中心穿出2~3cm;Step S2, sample installation: use degassed distilled water to completely saturate the clay plate on the steel bottom plate of the pressure chamber, and then put the root-containing sample into the pressure chamber so that the vertical side and the pressure chamber are transparent. Then, wrap the latex film on the side of the sample to seal the sample; then place an appropriate number of porous annular spacers on the upper part of the sample to control the raised area of the top of the sample during the root pulling process; A metal gasket is placed on the annular spacer, and the root system of the plant to be tested is pierced 2-3cm from the center of the porous annular spacer and the metal spacer;
步骤S3、根系拉拔装置安装:将根系拉拔装置的竖向拉拔装置的拉拔伸缩杆下端插入钢制顶盖的凸腔顶部的孔洞内,然后将根系拉拔装置的水平夹持装置的电机固定在拉拔伸缩杆下端;最后安装钢制顶盖,并将螺杆穿过钢制顶盖以及支撑管上的预留孔后与钢制底板上的螺纹孔螺纹连接,支撑管位于钢制顶盖和钢制底板之间、有机玻璃侧壁外围;Step S3, installation of root pulling device: insert the lower end of the pulling telescopic rod of the vertical pulling device of the root pulling device into the hole at the top of the convex cavity of the steel top cover, and then insert the horizontal clamping device of the root pulling device The motor is fixed on the lower end of the pulling and retracting rod; finally, the steel top cover is installed, and the screw is threaded through the steel top cover and the reserved holes on the support pipe and then connected with the threaded holes on the steel bottom plate, and the support pipe is located in the steel top cover. Between the top cover and the steel bottom plate, and the periphery of the plexiglass side wall;
步骤S4、设备启动:接通数据采集系统的计算机、数据采集箱,围压控制装置的围压控制器,以及吸力控制装置的反压控制器、气压控制器的电源并开机;Step S4, equipment startup: connect the computer of the data acquisition system, the data acquisition box, the confining pressure controller of the confining pressure control device, and the power supply of the back pressure controller and the air pressure controller of the suction control device and start up;
步骤S5、根系夹持:打开竖向拉拔装置的拉力机,通过液压控制拉力机的伸缩杆向下运动驱动拉拔伸缩杆向下运动,拉拔伸缩杆带动水平夹持装置向下移动至其夹片与待测的植物根系伸出金属垫片的部分对齐,然后关闭拉力机;将水平夹持装置的水平力传感器清零再打开电机,电机转动并通过两个螺纹旋杆和其上的螺母座经连接杆带动两个夹片固定杆向待测的植物根系方向靠近,同时在此过程中实时观测水平力传感器的读数,并在两个夹片上的橡胶垫夹紧待测的植物根系时关闭电机,记录此时水平力传感器的示数,即为水平夹持力;Step S5, root system clamping: turn on the pulling machine of the vertical pulling device, drive the pulling extension rod to move downward through the downward movement of the telescopic rod of the hydraulic control pulling machine, and the pulling extension rod drives the horizontal clamping device to move down to The clip is aligned with the part of the plant root system to be tested that protrudes from the metal gasket, and then the tension machine is turned off; the horizontal force sensor of the horizontal clamping device is reset to zero, and then the motor is turned on. The motor rotates and passes through the two threaded rods and the upper The nut seat drives the two clip fixing rods to approach the root system of the plant to be measured through the connecting rod. At the same time, the reading of the horizontal force sensor is observed in real time during this process, and the rubber pads on the two clips clamp the plant to be measured. When the root system is turned off, the motor is turned off, and the indication of the horizontal force sensor at this time is recorded, which is the horizontal clamping force;
步骤S6、施加围压:拧松钢制顶盖上的排气孔内的排气螺丝,打开进出水管阀门,通过围压控制装置的水泵抽取水缸内的蒸馏水经进出水管向压力室内部注入,当压力室内部蒸馏水缓慢从排气孔流出时,拧紧排气螺丝,关闭进出水管阀门;将围压控制器读数清零,再打开围压水管阀门,通过围压控制器设定试验所需施加的围压值,实时观测反压体积变化数据来判断试样固结是否完成;Step S6, applying confining pressure: loosen the exhaust screw in the exhaust hole on the steel top cover, open the valve of the water inlet and outlet, and pump the distilled water in the water tank through the water inlet and outlet pipes into the pressure chamber through the water pump of the confining pressure control device. , when the distilled water inside the pressure chamber slowly flows out from the exhaust hole, tighten the exhaust screw and close the valve of the inlet and outlet water pipes; clear the reading of the confining pressure controller to zero, then open the valve of the confining pressure water pipe, and set the test requirements through the confining pressure controller. The applied confining pressure value, real-time observation of back pressure volume change data to judge whether the consolidation of the sample is completed;
步骤S7、施加吸力:待围压值达到设定值并稳定后,将吸力控制装置的反压控制器和气压控制器读数清零,再打开反压水管阀门和进气管阀门,打开吸力控制装置的空气压缩机并通过反压控制器和气压控制器分别设定所需反压值和气压值,通过数据采集系统的数据采集箱实时采集反压体积变化,实时观测反压体积变化数据来判断吸力是否平衡;Step S7, apply suction: after the confining pressure value reaches the set value and stabilizes, clear the readings of the back pressure controller and air pressure controller of the suction control device to zero, then open the back pressure water pipe valve and the intake pipe valve, and open the suction control device The required back pressure value and air pressure value are set by the back pressure controller and the air pressure controller respectively, and the back pressure volume change is collected in real time through the data acquisition box of the data acquisition system, and the back pressure volume change data is observed in real time to judge. Whether the suction is balanced;
步骤S8、开启PIV:吸力平衡后,通过数据采集系统的计算机控制PIV测试装置的同步器使激光电源与CCD相机同步工作,激光器通过激光头在压力室呈透明状的侧面中发射激光,并打开LED灯,开始记录待测的植物根系和土颗粒的运动方向和速率;Step S8, turn on the PIV: after the suction is balanced, the computer of the data acquisition system controls the synchronizer of the PIV test device to make the laser power supply work synchronously with the CCD camera, and the laser emits laser light in the transparent side of the pressure chamber through the laser head, and turns on LED light, start to record the movement direction and speed of the plant roots and soil particles to be tested;
步骤S9、根系拉拔:打开电机,通过水平夹持装置向待测的植物根系施加设定的水平夹持力;然后将竖向拉拔装置的拉力传感器和位移传感器清零,再打开拉力机,使拉力机带动拉拔伸缩杆匀速率运动对待测的植物根系施加向上的拉拔力,位移传感器和拉力传感器实时记录试验中位移和拉拔力大小,直至待测的植物根系被拔出或被拔断;Step S9, root system pulling: turn on the motor, and apply the set horizontal clamping force to the root system of the plant to be measured through the horizontal clamping device; then clear the tension sensor and the displacement sensor of the vertical pulling device, and then turn on the tension machine , so that the pulling machine drives the pulling and retracting rod to move at a uniform rate and exerts upward pulling force on the root system of the plant to be tested. be pulled off;
步骤S10、系统复位:依次打开电机和拉力机,使水平夹持装置和拉拔伸缩杆复位,停止PIV测试装置,通过气压控制器和反压控制器将气压与反压调为零,并通过围压控制器将围压调为零;然后关闭反压水管阀门、进气管阀门和围压水管阀门,打开进出水管阀门和排气螺丝,通过进出水管将压力室内部的水排出,最后再打开压力室的钢制顶盖拆除试样;Step S10, system reset: turn on the motor and the tension machine in turn, reset the horizontal clamping device and the pulling and retractable rod, stop the PIV test device, adjust the air pressure and back pressure to zero through the air pressure controller and the back pressure controller, and pass the The confining pressure controller adjusts the confining pressure to zero; then close the back pressure water pipe valve, the intake pipe valve and the confining pressure water pipe valve, open the inlet and outlet water pipe valves and exhaust screws, discharge the water inside the pressure chamber through the inlet and outlet water pipes, and finally open it again The steel top cover of the pressure chamber is removed from the sample;
步骤S11、通过计算机对试验数据进行分析处理,得到不同围压和基质吸力作用下含根系土中不同龄期根系的抗拉拔特性参数。Step S11 , analyzing and processing the test data through a computer to obtain the characteristic parameters of the pull-out resistance of the roots of different ages in the root-containing soil under the action of different confining pressures and matrix suction.
进一步的,按照下述方法制备含待测单根的试样:量取待测单根的直径,按试验方案要求配置所需含水率的圆柱体试样,并在圆柱体试样中心放置待测单根,脱模后将圆柱体试样沿待测单根的中心切割成半圆柱体,制备成所需的含待测单根的试样;Further, prepare the sample containing the single root to be tested according to the following method: measure the diameter of the single root to be tested, configure the cylinder sample with the required moisture content according to the requirements of the test plan, and place the sample to be tested in the center of the cylinder sample. Measure a single root, after demoulding, cut the cylindrical sample into a semi-cylinder along the center of the single root to be tested, and prepare the required sample containing the single root to be tested;
然后对含待测单根的试样重复步骤S2~S10,并通过计算机分析处理对含待测单根的试样重复步骤S2~S10所得试验数据,得到不同围压和基质吸力作用下含根系土中不同龄期待测单根的抗拉拔特性参数,完成不同围压和基质吸力作用下含根系土中不同龄期的待测单根的根系拉拔试验。Then repeat steps S2 to S10 for the sample containing the single root to be tested, and repeat the test data obtained from steps S2 to S10 for the sample containing the single root to be tested through computer analysis to obtain the root-containing system under different confining pressures and matrix suction. The anti-pullout parameters of the single root in the soil of different ages are expected to be measured, and the root pull-out test of the single root to be tested in the root-containing soil of different ages under the action of different confining pressures and matrix suction is completed.
本发明实施例的有益效果是:The beneficial effects of the embodiments of the present invention are:
1.本发明实施例采用轴平移技术控制基质吸力,以考虑不同基质吸力对非饱和土体中植物根系抗拉拔特性的影响,从而真实模拟天然土体的干湿条件,尽可能还原植物根系所处天然环境状态,解决了现有仪器在测定根系的抗拉拔特性时无法考虑基质吸力对根系拉拔特性的影响的问题;1. The embodiment of the present invention adopts the axis translation technology to control the substrate suction, so as to consider the influence of different substrate suctions on the pull-out resistance of plant roots in unsaturated soils, thereby truly simulating the dry and wet conditions of natural soils and restoring plant roots as much as possible. It is in the natural environment, which solves the problem that the existing instruments cannot consider the influence of matrix suction on the root pulling characteristics when measuring the anti-pulling characteristics of roots;
2.本发明实施例以蒸馏水为介质,通过压力控制器在乳胶膜包裹的试样外侧施加不同水平的围压,模拟土体侧压力大小和应力历史,进而研究不同围压条件下土体中单根和根系的抗拉拔特性,解决了现有仪器在测定根系的抗拉拔特性时无法考虑围压对根系拉拔特性的影响的问题;2. In the embodiment of the present invention, distilled water is used as the medium, and different levels of confining pressure are applied on the outside of the sample wrapped by the latex film through the pressure controller to simulate the lateral pressure and stress history of the soil body, and then study the soil mass under different confining pressure conditions. The pull-out resistance of single root and root system solves the problem that the influence of confining pressure on root pull-out characteristics cannot be considered when measuring the pull-out resistance of root system by existing instruments;
3.本发明实施例采用粒子图像测速技术(PIV)对拉拔试验过程中土颗粒和植物根系运动方向和速率进行实时测量,从而探讨单根和根系拔出对附近土体的扰动程度及范围,并揭示相关机理,解决了现有仪器无法准确测定植物根系在土体中的滑移变形及其对周围土体的扰动程度和范围的问题。3. In the embodiment of the present invention, particle image velocimetry (PIV) is used to measure the movement direction and speed of soil particles and plant roots in real time during the pull-out test, so as to explore the degree and scope of disturbance to nearby soil by single root and root pull-out , and reveal the relevant mechanism, which solves the problem that the existing instruments cannot accurately measure the slip deformation of the plant root system in the soil and the degree and scope of the disturbance to the surrounding soil.
附图说明Description of drawings
为了更清楚地说明本发明实施例或现有技术中的技术方案,下面将对实施例或现有技术描述中所需要使用的附图作简单地介绍,显而易见地,下面描述中的附图仅仅是本发明的一些实施例,对于本领域普通技术人员来讲,在不付出创造性劳动的前提下,还可以根据这些附图获得其他的附图。In order to explain the embodiments of the present invention or the technical solutions in the prior art more clearly, the following briefly introduces the accompanying drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only These are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can also be obtained according to these drawings without creative efforts.
图1为本发明实施例的基于PIV技术的根系拉拔试验系统结构图(未画出PIV测试装置)。FIG. 1 is a structural diagram of a root pulling test system based on PIV technology according to an embodiment of the present invention (the PIV test device is not shown).
图2为本发明实施例的基于PIV技术的根系拉拔试验系统的局部结构图。FIG. 2 is a partial structural diagram of a root pulling test system based on PIV technology according to an embodiment of the present invention.
图3为本发明实施例的基于PIV技术的根系拉拔试验系统的压力室结构图。3 is a structural diagram of a pressure chamber of a root pulling test system based on the PIV technology according to an embodiment of the present invention.
图4为本发明实施例的基于PIV技术的根系拉拔试验系统的围压控制装置示意图。FIG. 4 is a schematic diagram of a confining pressure control device of a root system pulling test system based on PIV technology according to an embodiment of the present invention.
图5为本发明实施例的基于PIV技术的根系拉拔试验系统的吸力控制装置示意图。5 is a schematic diagram of a suction control device of a root pulling test system based on PIV technology according to an embodiment of the present invention.
图6为本发明实施例的基于PIV技术的根系拉拔试验系统的竖向拉拔装置示意图。6 is a schematic diagram of a vertical pulling device of a root system pulling test system based on the PIV technology according to an embodiment of the present invention.
图7为本发明实施例的基于PIV技术的根系拉拔试验系统的水平夹持装置示意图。7 is a schematic diagram of a horizontal clamping device of a root system pulling test system based on the PIV technology according to an embodiment of the present invention.
图8为本发明实施例的基于PIV技术的根系拉拔试验系统的PIV测试装置结构图。8 is a structural diagram of a PIV test device of a root pulling test system based on PIV technology according to an embodiment of the present invention.
图9为本发明实施例的基于PIV技术的根系拉拔试验系统的数据采集系统示意图。FIG. 9 is a schematic diagram of a data acquisition system of a root pulling test system based on PIV technology according to an embodiment of the present invention.
图中,1.压力室,2.围压控制装置,3.吸力控制装置,4.根系拉拔装置,5.PIV测试装置,6.数据采集系统,7.钢制底板,8.有机玻璃侧壁,9.钢制顶盖,10.支撑管,11.螺杆,12.试样,13.乳胶膜,14.有机玻璃固定板,15.陶土板,16.多孔环形垫块,17.金属垫片,18.进出水管接口,19.围压水管接口,20.反压水管接口,21.水泵、22.排水槽,23.曲板有机玻璃侧壁,24.平板有机玻璃侧壁,25.拉拔杆,26.进气管接口,27.排气孔,28.第二密封圈,29.排气螺丝,30.植物根系,31.围压水管,32.围压控制器,33.进出水管,34.水缸,35.反压控制器,36.空气压缩机,37.过滤器,38.干燥器,39.气压控制器,40.安全罐,41.反压水管,42.进气管,43.水平夹持装置,44.竖向拉拔装置,45.电机,46.螺纹旋杆,47.连接杆,48.橡胶垫,49.夹片,50.夹片固定杆,51.水平力传感器,52.拉力机,53.横梁,54.支架,55.底座,56.拉力传感器,57.位移传感器,58.位移测杆,59.夹持装置固定杆,60.拉拔伸缩杆,61.矩形测试腔,62.同步器,63.激光电源,64.激光器,65.激光头,66.CCD相机,67.LED灯,68.PIV连接线,69.计算机,70.数据采集箱,71.进出水管阀门,72.围压水管阀门,73.反压水管阀门,74.进气管阀门。In the figure, 1. Pressure chamber, 2. Confining pressure control device, 3. Suction control device, 4. Root pulling device, 5. PIV test device, 6. Data acquisition system, 7. Steel base plate, 8. Plexiglass Side wall, 9. Steel top cover, 10. Support tube, 11. Screw, 12. Sample, 13. Latex film, 14. Plexiglass fixing plate, 15. Clay plate, 16. Porous annular spacer, 17. Metal gasket, 18. Inlet and outlet water pipe interface, 19. Confining pressure water pipe interface, 20. Back pressure water pipe interface, 21. Water pump, 22. Drainage groove, 23. Curved plexiglass side wall, 24. Flat plexiglass side wall, 25. Drawing rod, 26. Intake pipe interface, 27. Exhaust hole, 28. Second sealing ring, 29. Exhaust screw, 30. Plant root system, 31. Confining pressure water pipe, 32. Confining pressure controller, 33 .Inlet and outlet pipes, 34. Water tank, 35. Back pressure controller, 36. Air compressor, 37. Filter, 38. Dryer, 39. Air pressure controller, 40. Safety tank, 41. Back pressure water pipe, 42 .Intake pipe, 43. Horizontal clamping device, 44. Vertical pulling device, 45. Motor, 46. Threaded rod, 47. Connecting rod, 48. Rubber pad, 49. Clip, 50. Clip fixing rod , 51. Horizontal force sensor, 52. Tension machine, 53. Beam, 54. Bracket, 55. Base, 56. Tension sensor, 57. Displacement sensor, 58. Displacement measuring rod, 59. Clamping device fixing rod, 60. Pull out telescopic rod, 61. Rectangular test cavity, 62. Synchronizer, 63. Laser power supply, 64. Laser, 65. Laser head, 66. CCD camera, 67. LED light, 68. PIV cable, 69. Computer, 70. Data acquisition box, 71. In and out water pipe valve, 72. Confining pressure water pipe valve, 73. Back pressure water pipe valve, 74. Intake pipe valve.
具体实施方式Detailed ways
下面将结合本发明实施例中的附图,对本发明实施例中的技术方案进行清楚、完整地描述,显然,所描述的实施例仅仅是本发明一部分实施例,而不是全部的实施例。基于本发明中的实施例,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他实施例,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 embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.
实施例1Example 1
本发明实施例提供一种基于PIV技术的根系拉拔试验系统,如图1~2所示,包括压力室1、围压控制装置2、吸力控制装置3、根系拉拔装置4、PIV测试装置5和数据采集系统6;压力室1整体为半圆柱体状密封结构,其侧面呈透明状,且压力室1内放置有半圆柱体状的试样12,试样12的竖直侧面内包含一条沿竖直方向从中心劈开的植物根系30。且植物根系30顶端露出于试样12顶部;所述围压控制装置2与压力室1双向连通,对压力室1内的试样12的围压进行调节;所述吸力控制装置3与压力室1双向连通,对压力室1内的试样12的基质吸力进行调节;所述根系拉拔装置4设置于试样12的上方,对植物根系30施加拉拔力;所述PIV测试装置5设置于压力室1呈透明状的侧面正前方,对土粒和植物根系30的运动轨迹和速率进行测定、记录;所述数据采集系统6与围压控制装置2、吸力控制装置3、PIV测试装置5双向电性连接,并与根系拉拔装置4的信号输出端电性连接。An embodiment of the present invention provides a root pulling test system based on PIV technology, as shown in Figures 1-2, including a pressure chamber 1, a confining pressure control device 2, a
压力室1为根系拉拔试验的主要发生装置,如图2~3所示,包括钢制底板7、有机玻璃侧壁8、钢制顶盖9和试样12,钢制顶盖9、有机玻璃侧壁8、钢制底板7从上到下依次固定连接形成半圆柱体状密封空间,试样12位于半圆柱体状密封空间内,且有机玻璃侧壁8竖直设置于试样12的侧面外围,有机玻璃侧壁8顶部与钢制顶盖9的底面密封连接,有机玻璃侧壁8底部与钢制底板7的顶面密封连接。The pressure chamber 1 is the main generating device for the root pull test, as shown in Figures 2 to 3, including a steel bottom plate 7, a
如图2所示,有机玻璃侧壁8由曲板有机玻璃侧壁23和平板有机玻璃侧壁24密封连接形成,其中,曲板有机玻璃侧壁23设置在试样12的曲状侧面外围,平板有机玻璃侧壁24设置在试样12的竖直侧面正前方,曲板有机玻璃侧壁23和平板有机玻璃侧壁24分别与钢制底板7的顶面以及钢制顶盖9的底面密封连接。As shown in FIG. 2 , the
具体的,钢制底板7的顶面和钢制顶盖9的底面上下竖直对应设置有用于固定有机玻璃侧壁8的凹槽,有机玻璃侧壁8底部嵌入钢制底板7顶面的用于固定有机玻璃侧壁8的凹槽内,并通过玻璃胶密封连接防止漏水;有机玻璃侧壁8顶部嵌入钢制顶盖9底面的用于固定有机玻璃侧壁8的凹槽内,且两者通过位于钢制顶盖9底面的凹槽内的第一密封圈密封连接。曲板有机玻璃侧壁23和平板有机玻璃侧壁24之间采用嵌入后加玻璃胶密封的方式密封连接,具体的,曲板有机玻璃侧壁23与平板有机玻璃侧壁24连接部位设计成凸字形,平板有机玻璃侧壁24与曲板有机玻璃侧壁23连接部位对应设计成凹字形,平板有机玻璃侧壁24与曲板有机玻璃侧壁23通过凹凸部位组合嵌入,嵌入后在接缝内外均采用玻璃胶密封。Specifically, the top surface of the steel bottom plate 7 and the bottom surface of the
所述曲板有机玻璃侧壁23的外围设置有多个支撑管10,钢制顶盖9和支撑管10上均设置有竖直贯穿其的预留孔,钢制底板7顶面设置有与钢制顶盖9上的预留孔一一对应的螺纹孔,钢制顶盖9和钢制底板7通过螺杆11连接,螺杆11从上到下依次穿过钢制顶盖9、支撑管10上的预留孔后与钢制底板7上的螺纹孔螺纹连接。由于试验时需要向压力室1内施加较大水压,故压力室1要承受较大压力,支撑管10起到支撑的作用,对有机玻璃侧壁8进行防护。其次,相比于压力室1的侧壁,压力室1的钢制顶盖9和钢制底板7还需起到上下密封压力室1的作用,因此通过螺杆11对两者进行固定。A plurality of
所述钢制底板7上表面中间区域设有漏斗型的排水槽22,排水槽22顶部固定有陶土板15,试样12放置在陶土板15上。钢制底板7一侧设有带进出水管阀门71的进出水管接口18、带围压水管阀门72的围压水管接口19和带反压水管阀门73的反压水管接口20;进出水管接口18和围压水管接口19的一端与压力室1内部连通,进出水管接口18和围压水管接口19的另一端与围压控制装置2连通;反压水管接口20的一端与排水槽22底部连通,其另一端与吸力控制装置3连通。A funnel-shaped
所述试样12的曲状侧面包裹有乳胶膜13,乳胶膜13在平展开时为长方形,其宽度与试样12的高度相同,其长度大于试样12的曲状侧面底部边长;乳胶膜13两侧多出来的部分沿有机玻璃侧壁8的平板侧壁(平板有机玻璃侧壁24)向远离试样12的方向展开,并通过有机玻璃固定板14固定压实在有机玻璃侧壁8的平板侧壁(平板有机玻璃侧壁24)上,使乳胶膜13密封住试样12。具体做法是在乳胶膜13两侧多出部分沿有机玻璃侧壁8的平板侧壁向远离试样12的方向展开后,将有机玻璃固定板14底部嵌入钢制底板7顶面,由于有机玻璃固定板14为刚性材料,而乳胶膜13可压缩,因此在有机玻璃固定板14一端固定后会对乳胶膜13产生一定的挤压力,从而将乳胶膜13紧贴平板有机玻璃侧壁24。如图2所示,有机玻璃固定板14位于钢制底板7和钢制顶盖9之间并与钢制底板7以及钢制顶盖9可拆卸连接,具体的,钢制底板7的顶面和钢制顶盖9的底面上均上下对应设置有用于连接有机玻璃固定板14的凹槽,有机玻璃固定板14顶部嵌入钢制顶盖9底面的用于连接有机玻璃固定板14的凹槽内,有机玻璃固定板14底部嵌入钢制底板7顶面的用于连接有机玻璃固定板14的凹槽内。The curved side of the
所述钢制顶盖9上设有与试样12上下对应的凸腔,凸腔顶部留有用于根系拉拔装置4的拉拔杆25伸出的孔洞,孔洞周围设第二密封圈28,以保证压力室1的气密性。钢制顶盖9的凸腔处还设有与凸腔内部连通的带进气管阀门74的进气管接口26,压力室1通过进气管接口26与吸力控制装置3相连。此外,钢制顶盖9上还设有与试样12所在的半圆柱体状密封空间连通的排气孔27,排气孔27内设有与其螺纹连接的排气螺丝29,排气孔27的开闭由带第三密封圈的排气螺丝29控制,并可通过排气螺丝29与排气孔27连接的松紧程度来调节排气的速率,排气孔27用于在向压力室1注水时或在压力室1排水时维持压力室1内外气压平衡。The
所述试样12上表面设置有多个依次嵌套的多孔环形垫块16,多孔环形垫块16上设置有金属垫片17,金属垫片17位于多孔环形垫块16和钢制顶盖9之间,在使用多块多孔环形垫块16的情形下,最内侧的多孔环形垫块16没有被钢制顶盖9压住,在试验过程中可能会松动,无法起到控制试样顶部隆起面积的作用,而通过金属垫片17可以约束多孔环形垫块16,从而控制根系拉拔过程中试样顶部隆起面积。使用不同数量的多孔环形垫块16嵌套可控制试样12顶部在植物根系30被拔出时的容许隆起面积,如对于根茎较粗的根系,要预留较大的隆起面积,可使用较少的多孔环形垫块16嵌套;对于根茎较细的根系,只需预留较小的面积,可使用较多的多孔环形垫块16。The upper surface of the
多孔环形垫块16为多孔结构,其顶面和侧面均有贯通的孔洞供气体流通,多孔环形垫块16设置为多孔结构是由于试验过程中吸力控制装置3会通过进气管接口26向试样12内部施加气压,将多孔环形垫块16设置为多孔结构能让气压更均匀地从顶部向试样12施加。The porous
围压控制装置2用于调节压力室1内的试样12所承受的环向压力,模拟土体所受的不同的应力状态。如图4所示,围压控制装置2包括围压水管31、围压控制器32、进出水管33、水缸34和水泵21。水泵21位于水缸34内,且水泵21通过进出水管33与压力室1的进出水管接口18连通,围压控制装置2可通过水泵21抽取水缸34内的蒸馏水向压力室1内部注水或将压力室1内部的水排出至水缸34;围压控制器32通过围压水管31与压力室1的围压水管接口19连通,围压控制器32用于实时控制和测量压力室1内试样12的围压以及围压水管31进出水的体积,围压控制器32是一个内部可储存一定水的控制器,主要由水泵,储水腔、控制器、传感器组成,可采用英国GDS公司生产的ADVDPC型高级压力/体积控制器。围压控制器32的信号输出端与数据采集系统6的数据采集箱70的输入端电性连接,围压控制器32的信号输入端与数据采集系统6的计算机69电性连接,计算机69控制围压控制器32工作,围压控制器32向数据采集箱70实时传输测量的压力室1内试样12的围压大小以及围压水管31进出水体积的变化值。The confining pressure control device 2 is used to adjust the hoop pressure on the
吸力控制装置3主要用于控制压力室1内试样12的基质吸力,如图5所示,吸力控制装置3包括反压控制器35、空气压缩机36、过滤器37、干燥器38、气压控制器39、安全罐40、反压水管41和进气管42;反压控制器35通过反压水管41与压力室1的反压水管接口20相连;进气管42一端与压力室1的进气管接口26连接,其另一端依次经安全罐40、气压控制器39、干燥器38、过滤器37与空气压缩机36连接。空气压缩机36用于提供气压力,过滤器37用于过滤压缩空气中的固体颗粒和杂质,干燥器38可对压缩空气进行干燥。反压控制器35用于实时控制和测量压力室1内试样12的孔隙水压力和反压水管41进出水的体积,反压控制器35与围压控制器32的内部结构一致。气压控制器39用于控制和测量施加给试样12的孔隙气压力,具体通过调节空气压缩机36输出的空气压力,然后向压力室1输出所需压力的空气来实现。反压控制器35和气压控制器39的信号输出端与数据采集系统6的数据采集箱70的输入端电性连接,反压控制器35和气压控制器39的信号输入端与数据采集系统6的计算机69电性连接,计算机69控制反压控制器35和气压控制器39工作,反压控制器35向数据采集箱70实时传输测得的试样12的孔隙水压力和反压水管41进出水体积的变化值,气压控制器39向数据采集箱70实时传输测得的试样12的孔隙气压力。安全罐40用于当试样12中的水从进气管42排出时收集水分,防止损坏气压控制器39。The
根系拉拔装置4包括水平夹持装置43和竖向拉拔装置44,如图6~7所示,水平夹持装置43用于向试样12内的植物根系30提供水平的夹持力,竖向拉拔装置44用于向土体中植物根系30提供竖向的拉拔力。竖向拉拔装置44下端经经钢制顶盖9的凸腔顶部的孔洞伸入该凸腔内,水平夹持装置43设置于钢制顶盖9的凸腔内,且水平夹持装置43固定在竖向拉拔装置44下端,竖向拉拔装置44可带动水平夹持装置43在压力室1内竖直向下移动。如图6所示,竖向拉拔装置44包括拉力机52、横梁53、支架54、底座55、拉拔杆25、拉力传感器56、位移传感器57和位移测杆58,底座55与横梁53通过支架54固定连接,压力室1固定于底座55上,拉力机52的伸缩杆设置于横梁53上;拉拔杆25顶部穿过横梁53与拉力机52连接,其底部经钢制顶盖9的凸腔顶部的孔洞伸入压力室1内与水平夹持装置43连接;拉拔杆25与水平夹持装置43的外壳为同一材质,之间可采用焊接的方式进行连接。拉力机52的伸缩杆与拉拔杆25之间固定有拉力传感器56,横梁53底部竖直固定有位移传感器57;拉拔杆25由夹持装置固定杆59和拉拔伸缩杆60组成,拉拔伸缩杆60顶部与夹持装置固定杆59底部可拆卸连接,具体的,拉拔伸缩杆60顶部设置有外螺纹,夹持装置固定杆59底部设置有内螺纹,夹持装置固定杆59底部与拉拔伸缩杆60顶部螺纹连接。位移传感器57的指针头接触位移测杆58,实时记录植物根系30竖直方向的位移,拉力传感器56和位移传感器57的输出端均与数据采集系统6的数据采集箱70连接。The root system pulling device 4 includes a
拉拔杆25为中空设计,即拉拔伸缩杆60与夹持装置固定杆59为中空设计。且夹持装置固定杆59可由内层和外层组成,内层和外层可相对运动,其内层底部设置有内螺纹,夹持装置固定杆59的内层底部与拉拔伸缩杆60顶部螺纹连接;夹持装置固定杆59的内层顶部与拉力传感器56底部连接,拉力传感器56顶部与拉力机52的伸缩杆底部固定连接,连接可采用螺栓、铆接、焊接等方式。拉力机52可以采用空心液压千斤顶。The drawing
如图7所示,水平夹持装置43包括电机45、螺纹旋杆46、连接杆47、橡胶垫48、夹片49、夹片固定杆50和水平力传感器51,电机45为双向同步电机,电机45的两个输出轴分别连接一个螺纹旋杆46,每个螺纹旋杆46上螺纹连接有螺母座,每个螺母座底部经连接杆47固定连接水平放置的夹片固定杆50,两个螺纹旋杆46上的螺母座经连接杆47固定连接的夹片固定杆50端部相向设置,两个夹片固定杆50相互靠近的一端分别活动连接有夹片49,夹片固定杆50在螺纹旋杆46的带动下可沿夹片49内部滑动,夹片49内部固定有水平力传感器51,夹片固定杆50位于夹片49内部的一端端部与嵌入夹片49内的水平力传感器51接触。为保证螺纹旋杆46的稳定性,可将其设置于水平夹持装置外壳内,其一端与电机45的输出轴固定连接,其另一端通过轴承等与水平夹持装置外壳活动连接,水平夹持装置外壳底部设置有方便连接杆47左右移动的开口。As shown in FIG. 7 , the
具体的,两个夹片固定杆50相互靠近的一端从夹片49背部伸入夹片49的内部,夹片49内设置有沿夹片固定杆50的长度方向设置的滑槽,夹片固定杆50伸入夹片49内部的一端边缘设置有凸起,夹片固定杆50上的凸起与夹片49内的滑槽匹配连接,且夹片固定杆50上的凸起可沿夹片49内的滑槽移动;夹片49内部与夹片固定杆50之间留有空隙,上、下空隙内涂抹润滑油减小夹片固定杆50在夹片49内移动的阻力;夹片49与植物根系30接触面紧贴橡胶垫48。夹片49可通过夹片固定杆50的伸缩来夹持植物根系30和施加水平夹持力,夹片固定杆50在螺纹旋杆46的带动下可沿夹片49内部滑动,且夹片固定杆50在夹片49内部滑动至尽头后会在螺纹旋杆46的作用下带动夹片49一起向靠近或远离植物根系30的方向移动。水平力传感器51的输出端经穿过拉拔杆25内部空间的连接线与压力室1外部的数据采集系统6的数据采集箱70连接。Specifically, one end of the two
竖向拉拔装置44置于试验台上,水平夹持装置43与竖向拉拔装置44通过拉拔伸缩杆60下端的螺纹以及电机45顶部的螺纹孔进行螺纹连接。水平夹持装置43的导线从空心的拉拔伸缩杆60内部引出连接到数据采集系统6的数据采集箱70,该导线在电机45的顶部设有接口,可以连接或断开。试验前,水平夹持装置43从竖向拉拔装置44的拉拔伸缩杆60上拧下,并断开导线,取下水平夹持装置43,如此才可以打开压力室1的钢制顶盖9。安装试样后,先连接水平夹持装置3的导线,然后将水平夹持装置43与竖向拉拔装置44之间通过拉拔伸缩杆60与电机45顶部的螺纹进行连接,最后安装压力室1的钢制顶盖9,从而实现根系拉拔装置4的整体组装。The vertical pulling
PIV测试装置5可测定土粒和植物根系30的运动轨迹和速率,如图8所示,PIV测试装置5包括矩形测试腔61、同步器62、激光电源63、激光器64、激光头65、CCD相机66、LED灯67和PIV连接线68。矩形测试腔61与压力室1均固定于竖向拉拔装置44的底座55上,矩形测试腔61位于压力室1正前方,且矩形测试腔61是由矩形钢制顶板、矩形钢制底板、三面矩形钢制侧壁以及压力室1呈透明状的侧面(平板有机玻璃侧壁24)共同形成的密闭空间。激光头65安装在压力室1的平板有机玻璃侧壁24前方下部,激光头65与激光器64的输出端电性连接,激光电源63与激光器64的电源端电性连接。矩形测试腔61与平板有机玻璃侧壁24相对设置的钢制侧壁内部中心位置固定有CCD相机66,同步器62连接CCD相机66与激光电源63,同步器62通过PIV连接线68与数据采集系统6的计算机69双向连接,以CCD相机66为中心,在其四周各设置一个LED灯67,保证CCD相机66拍摄面视野明亮清晰,同步器62用于同步激光电源63与CCD相机66的工作频率,在激光器64发射激光的同时通过CCD相机66记录有效数据。The PIV test device 5 can measure the movement trajectory and speed of soil particles and
数据采集系统6用于记录试验过程中的各类数据变化,如图9所示,数据采集系统6包括数据采集箱70和计算机69,数据采集箱70的输入端分别与围压控制装置2的围压控制器32、吸力控制装置3的反压控制器35、吸力控制装置3的气压控制器39,以及根系拉拔装置4的水平力传感器51、拉力传感器56、位移传感器57的信号输出端电性连接,所述数据采集箱70的输出端以及围压控制器32、反压控制器35、气压控制器39的信号输入端均与计算机69电性连接,PIV测试装置5的CCD相机66直接与计算机69双向连接,试验数据由计算机69直接采集。The data acquisition system 6 is used to record various data changes during the test. As shown in FIG. 9 , the data acquisition system 6 includes a
本发明实施例压力室1内部尺寸为:直径300mm,高150mm;试样12的尺寸为:直径200mm,高100mm,且压力室1和试样12的尺寸可以根据实际需求调整;水平力传感器51和拉力传感器56量程为10kN,精度为0.001kN;位移传感器57量程为0±200mm,精度为0.001mm;螺纹旋杆最大调节位移:20mm;夹片最大夹持力:2kN;拉力机最大拉力:10kN;围压控制器32压力控制范围为0~2MPa,体积控制范围为0~100000mm3,压力精度为0.1kPa,体积精度为0.1mm3;反压控制器35压力控制范围为0~2MPa,体积控制范围为0~100000mm3,压力精度为0.1kPa,体积精度为0.1mm3;气压控制器39压力控制范围为0~2MPa,压力精度为0.1kPa;CCD相机66最大采样频率为15Hz;陶土板15进气值为1500kPa。The internal dimensions of the pressure chamber 1 in the embodiment of the present invention are: 300 mm in diameter and 150 mm in height; the dimensions of the sample 12 are: 200 mm in diameter and 100 mm in height, and the dimensions of the pressure chamber 1 and the sample 12 can be adjusted according to actual needs; the horizontal force sensor 51 And tension sensor 56 has a range of 10kN and an accuracy of 0.001kN; displacement sensor 57 has a range of 0±200mm and an accuracy of 0.001mm; the maximum adjustment displacement of the threaded rod: 20mm; the maximum clamping force of the clip: 2kN; the maximum tension of the tension machine: 10kN; the pressure control range of the confining pressure controller 32 is 0~2MPa, the volume control range is 0~100000mm 3 , the pressure accuracy is 0.1kPa, and the volume accuracy is 0.1mm 3 ; the pressure control range of the back pressure controller 35 is 0~2MPa, The volume control range is 0~100000mm 3 , the pressure precision is 0.1kPa, and the volume precision is 0.1mm 3 ; the pressure control range of the air pressure controller 39 is 0~2MPa, and the pressure precision is 0.1kPa; the maximum sampling frequency of the CCD camera 66 is 15Hz; The plate 15 intake value is 1500 kPa.
本实施例的围压控制器32和反压控制器35均可选用英国GDS公司(GeotechnicalDigital Systems Instruments Ltd)生产的ADVDPC型高级压力/体积控制器;空气压缩机36可选用浙江劳士顿焊接设备有限公司生产的LAHW-1030型静音无油空气压缩机;过滤器37可选用厦门齐进工贸有限公司生产的VFL-66型真空专用直通式过滤器;干燥器38可选用温岭市金宇通用设备有限公司生产的02/0.8MPa型油水过滤器;气压控制器39可选用英国GDS公司生产的GDSPPC型气压控制器;电机45可选用深圳市兆威机电股份有限公司生产的ZWBPD032032-4型电机;水平力传感器51和拉力传感器56可选用上海质展测控系统有限公司生产的ZZ210-010型拉压力双向力学传感器;拉力机52可选用济南美特斯测试技术有限公司生产的电子拉力试验机;位移传感器57可选用深圳市米朗科技有限公司生产的MTR磁拖式防水型直线位移传感器;CCD相机66、激光器64、和PIV连接线68可选用北京立方天地科技发展有限公司生产的2D2C PIV系统;LED灯67可选用OPPLE公司生产的JU-LE-41489型灯泡;数据采集箱70可选用英国GDS公司生产的ADVDCS V2型高速数字控制与采集系统。Both the confining pressure controller 32 and the back pressure controller 35 in this embodiment can be selected from the ADVDPC type advanced pressure/volume controller produced by British GDS (Geotechnical Digital Systems Instruments Ltd); the air compressor 36 can be selected from Zhejiang Lawston welding equipment LAHW-1030 silent oil-free air compressor produced by Co., Ltd.; filter 37 can choose VFL-66 vacuum special straight-through filter produced by Xiamen Qijin Industry and Trade Co., Ltd.; dryer 38 can choose Wenling Jinyu general equipment The 02/0.8MPa oil-water filter produced by Co., Ltd.; the air pressure controller 39 can choose the GDSPPC air pressure controller produced by the British GDS company; the motor 45 can choose the ZWBPD032032-4 motor produced by Shenzhen Zhaowei Electromechanical Co., Ltd.; The horizontal force sensor 51 and the tensile force sensor 56 can be selected from the ZZ210-010 tension and pressure bidirectional mechanical sensor produced by Shanghai Qizhan Measurement and Control System Co., Ltd.; the tensile force machine 52 can be selected from the electronic tensile force testing machine produced by Jinan Meites Testing Technology Co., Ltd.; displacement The sensor 57 can be selected from the MTR magnetic drag type waterproof linear displacement sensor produced by Shenzhen Milang Technology Co., Ltd.; the CCD camera 66, the laser 64, and the PIV cable 68 can be selected from the 2D2C PIV system produced by Beijing CubeTiandi Technology Development Co., Ltd.; The LED lamp 67 can be selected from the JU-LE-41489 bulb produced by OPPLE Company; the data acquisition box 70 can be selected from the ADVDCS V2 high-speed digital control and acquisition system produced by the British GDS Company.
实施例2Example 2
参考图1~9,本发明实施例提一种基于PIV技术的根系拉拔试验方法,进行不同围压和基质吸力作用下含根系土中根系的抗拉拔试验,采用实施例1中所述的基于PIV技术的根系拉拔试验系统,操作步骤如下:With reference to Fig. 1~9, the embodiment of the present invention proposes a kind of root system pull-out test method based on PIV technology, carries out the pull-out test of root system in root-containing soil under the action of different confining pressure and matrix suction, adopts the method described in Example 1 The root pulling test system based on PIV technology, the operation steps are as follows:
步骤S1、试样准备:在试验箱内先铺设50~60mm厚的试验用土,将待测植物种子放入试验箱中心位置,再用试验土填满试验箱,然后定期浇水培育;待植物生长至试验所需程度时,去除土表以上植物花、茎、叶,仅保留根系,再采用圆柱形模具以根系为中心取样;脱模后将圆柱体试样沿根系中心竖向切割成半圆柱体,制备得到试验所需的含根系的试样12;Step S1, sample preparation: first lay 50~60mm thick test soil in the test box, put the plant seeds to be tested into the center of the test box, then fill the test box with the test soil, and then water regularly to cultivate; When the growth reaches the level required for the test, remove the flowers, stems, and leaves of the plants above the soil surface, and keep only the root system, and then use a cylindrical mold to take the root system as the center; after demoulding, cut the cylindrical sample vertically along the center of the root system into half. Cylinder, to prepare the
步骤S2、试样安装:用脱气蒸馏水对压力室1的钢制底板7上的陶土板15进行完全饱和,再将含根系的试样12放入压力室1内,使其竖直侧面与压力室1呈透明状的侧面(平板有机玻璃侧壁24)相接触,然后包裹乳胶膜13,乳胶膜13两侧多出来的部分沿有机玻璃侧壁8的平板侧壁向远离试样12的方向展开,并安装有机玻璃固定板14压紧乳胶膜13,使乳胶膜13密封住试样12,然后在试样12上部放置合适数量的多孔环形垫块16,控制根系拉拔过程中试样顶部隆起面积;再在多孔环形垫块16上放置金属垫片17,并使待测的植物根系30从多孔环形垫块16与金属垫片17中心穿出2~3cm;Step S2, sample installation: use degassed distilled water to completely saturate the
步骤S3、根系拉拔装置安装:将竖向拉拔装置44的拉拔伸缩杆60下端插入钢制顶盖9的凸腔顶部孔洞内,然后通过拉拔伸缩杆60下端的螺纹与水平夹持装置43的电机45顶部的螺纹将水平夹持装置43螺纹连接在拉拔伸缩杆60下端;最后安装钢制顶盖9,并将螺杆11穿过钢制顶盖9和支撑管10上的预留孔与钢制底板7上的螺纹孔螺纹连接;Step S3, installation of the root system pulling device: insert the lower end of the pulling
步骤S4、设备启动:接通计算机69、数据采集箱70、围压控制器32、反压控制器35和气压控制器39的电源并开机;Step S4, equipment startup: turn on the power of the
步骤S5、根系夹持:打开拉力机52,通过液压控制拉力机52的伸缩杆向下运动驱动拉拔伸缩杆60向下运动,拉拔伸缩杆60带动水平夹持装置43向下移动至夹片49与待测的植物根系30伸出金属垫片17的部分对齐,然后关闭拉力机;将水平力传感器51清零再打开电机45,电机45转动并通过两个螺纹旋杆46和连接杆47带动两个夹片固定杆50向待测的植物根系30方向靠近,同时在此过程中实时观测水平力传感器51的读数,并在两个夹片49上的橡胶垫48夹紧待测的植物根系30时关闭电机45,记录此时水平力传感器51的示数,即为水平夹持力;Step S5, root system clamping: open the
步骤S6、施加围压:拧松钢制顶盖9上的排气螺丝29,打开进出水管阀门71,通过水泵21抽取水缸34内的蒸馏水经进出水管33向压力室1内部注入,当压力室1内部蒸馏水缓慢从排气孔27流出时,拧紧排气螺丝29,关闭进出水管阀门71;将围压控制器32读数清零,再打开围压水管阀门72,通过围压控制器32设定试验所需施加的围压值,实时观测反压体积变化数据来判断试样固结是否完成;Step S6, applying confining pressure: loosen the
实时监测反压体积变化是由于试样固结是否完成的判定是依据反压体积在一个时间段内的变化是否超过某个限值,等吸力固结稳定判断标准为:连续2h内试样排水量即反压体积变化不超过0.01cm3,且总历时不少于48h,可以通过读取的围压控制器32或计算机69的数据判断是否达到设定值。The real-time monitoring of the back pressure volume change is due to the determination of whether the consolidation of the sample is completed or not based on whether the change of the back pressure volume in a period of time exceeds a certain limit. That is, the back pressure volume change does not exceed 0.01cm 3 , and the total duration is not less than 48 hours, and it can be judged whether the set value is reached by reading the data of the confining
步骤S7、施加吸力:待围压值达到设定值并稳定后,将反压控制器35和气压控制器39读数清零,再打开反压水管阀门73和进气管阀门74,打开空气压缩机36后通过反压控制器35和气压控制器39分别设定所需反压值和气压值,通过数据采集箱70实时采集反压体积变化,实时观测反压体积变化数据来判断吸力是否平衡;Step S7, applying suction: after the confining pressure value reaches the set value and stabilizes, clear the readings of the
步骤S8、开启PIV:吸力平衡后,通过计算机69控制同步器62使激光电源63与CCD相机66同步工作,激光器64通过激光头65在压力室1呈透明状的侧面即平板有机玻璃侧壁24中发射激光,并打开LED灯67,开始记录植物根系30和土颗粒的运动方向和速率;Step S8, turn on PIV: after the suction is balanced, the
步骤S9、根系拉拔:打开电机45,通过水平夹持装置43向待测的植物根系30施加设定的水平夹持力;然后将拉力传感器56和位移传感器57清零,再打开拉力机52,使拉力机52带动拉拔伸缩杆60匀速率运动对待测的植物根系30施加向上的拉拔力,位移传感器57和拉力传感器56实时记录试验中位移和拉拔力大小,直至待测的植物根系30被拔出或被拔断;Step S9, root system pulling: turn on the
拉力传感器56和位移传感器57均是试验开始后测定的纵向拉力与纵向位移,在施加水平夹持力后将拉力传感器56和位移传感器57清零,是为了减小水平夹持力施加过程对两个传感器的影响,尽可能减小试验误差。The
步骤S10、系统复位:依次打开电机45和拉力机52,使水平夹持装置43和拉拔伸缩杆60复位,停止PIV测试装置5,通过气压控制器39和反压控制器35将气压与反压调为零,并通过围压控制器32将围压调为零;然后关闭反压水管阀门73、进气管阀门74和围压水管阀门72,打开进出水管阀门71和压力室1的排气螺丝29,通过进出水管33将压力室1内部水排出,最后再打开压力室1的钢制顶盖9拆除试样12;Step S10, system reset: turn on the
步骤S11、通过计算机69对试验数据进行分析处理,可得到不同围压和基质吸力作用下含根系土中不同龄期根系的抗拉拔特性参数(主根抗拉强度和根系抗拔力),并分析拉拔过程中土体及植物根系的变形和运动轨迹,探讨根系拉拔过程对土体的扰动范围,揭示相关机理。In step S11, the test data is analyzed and processed by the
实施例3Example 3
参考图1~9,本发明实施例提另一种基于PIV技术的根系拉拔试验系统的使用方法,用于测试单根植物根系的抗拉拔试验,操作步骤如下:With reference to Fig. 1~9, the embodiment of the present invention proposes another kind of using method of the root system pulling test system based on PIV technology, for testing the pulling resistance test of single root plant root system, the operation steps are as follows:
步骤1、用游标卡尺量取待测单根的直径,按试验方案要求配置所需含水率的圆柱体试样,并在圆柱体试样中心放置待测单根(单根指根系中的一条根),脱模后将圆柱体试样沿待测单根的中心切割成半圆柱体,制备成试验所需的含待测单根的试样12;Step 1. Use a vernier caliper to measure the diameter of the single root to be tested, configure a cylindrical sample with the required moisture content according to the requirements of the test plan, and place the single root to be tested in the center of the cylindrical sample (single root refers to a root in the root system. ), after demoulding, cut the cylindrical sample into a semi-cylindrical body along the center of the single root to be tested, and prepare the
量取待测单根的直径是为了计算待测单根的抗拉强度,抗拉强度等于抗拔力除以待测单根的截面积,计算时将待测单根的截面近似成圆形。The purpose of measuring the diameter of the single root to be tested is to calculate the tensile strength of the single root to be tested. The tensile strength is equal to the pullout force divided by the cross-sectional area of the single root to be tested. When calculating, the cross-section of the single root to be tested is approximated as a circle. .
步骤2、对含待测单根的试样12重复步骤S2~S10;Step 2. Repeat steps S2 to S10 for the
步骤3、通过计算机69对试验数据进行分析处理,得到不同围压和基质吸力作用下含根系土中不同龄期待测单根的抗拉拔特性参数(抗拉强度、抗拔力和根土界面摩擦系数),并分析拉拔过程中土体及植物单根的变形和运动轨迹,探讨单根拉拔过程对土体的扰动范围,揭示相关机理。
以上所述仅为本发明的较佳实施例而已,并非用于限定本发明的保护范围。凡在本发明的精神和原则之内所作的任何修改、等同替换、改进等,均包含在本发明的保护范围内。The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the protection scope of the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention are included in the protection scope of the present invention.
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