WO2017084232A1 - 零应变土压力传感器 - Google Patents

零应变土压力传感器 Download PDF

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Publication number
WO2017084232A1
WO2017084232A1 PCT/CN2016/077926 CN2016077926W WO2017084232A1 WO 2017084232 A1 WO2017084232 A1 WO 2017084232A1 CN 2016077926 W CN2016077926 W CN 2016077926W WO 2017084232 A1 WO2017084232 A1 WO 2017084232A1
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hydraulic oil
elastic film
oil chamber
strain
zero
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French (fr)
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苏栋
江月琴
包小华
余中良
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Shenzhen University
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Shenzhen University
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Priority to US15/771,386 priority Critical patent/US10451492B2/en
Publication of WO2017084232A1 publication Critical patent/WO2017084232A1/zh
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
    • G01L1/00—Measuring force or stress, in general
    • G01L1/08—Measuring force or stress, in general by the use of counterbalancing forces
    • G01L1/083—Measuring force or stress, in general by the use of counterbalancing forces using hydraulic or pneumatic counterbalancing forces
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
    • G01L1/00—Measuring force or stress, in general
    • G01L1/02—Measuring force or stress, in general by hydraulic or pneumatic means
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
    • G01L1/00—Measuring force or stress, in general
    • G01L1/08—Measuring force or stress, in general by the use of counterbalancing forces
    • 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
    • G01N33/24—Earth materials

Definitions

  • the invention relates to the field of earth pressure measurement, in particular to a zero strain earth pressure sensor.
  • the zero-strain earth pressure sensor is a test tool used for on-site soil stress measurement. At present, the test is mainly carried out by converting non-electricity (pressure) into electricity. Zero-strain earth pressure sensor needs to be used in most cases.
  • the structure is buried in the soil medium, and the sensor and the soil medium are coordinated and deformed.
  • the test quantity is mainly the deformation (strain) of the structure, and the main converted electric quantity includes inductance, capacitance, resistance, frequency, electric charge, etc., so zero strain earth pressure
  • the main forms of sensors include piezoelectric, vibrating wire, inductive, capacitive, and resistive. The most widely used ones are vibrating wire and resistive, and the test quantities are frequency and voltage, respectively.
  • the principle of the resistive sensor is to convert the physical quantity of the structure into a measurable quantity by utilizing the relationship between the resistance of the wire (sheet) and its structural change.
  • the vibrating wire sensor makes the steel string and the sensor structure coordinately deform, and the magnitude of the stress on the string is induced by the oscillation of the steel string under electromagnetic excitation.
  • Piezoelectric crystal sensor is a promising dynamic stress test sensor. Piezoelectric crystal refers to a kind of crystal that can generate electric charge on its vertical surface when a load is applied to a specific surface of the crystal, and the electric charge disappears after unloading.
  • the present invention provides a zero-strain earth pressure sensor that measures more accurately.
  • the invention provides a zero strain earth pressure sensor, comprising a casing, a processor, an outer elastic film, an inner elastic film, an outer strain bridge connected to the outer elastic film, and an internal strain connected to the inner elastic film a bridge
  • the casing is provided with a hydraulic oil chamber and is disposed in the hydraulic oil chamber a lower end cavity
  • the outer elastic film is disposed at an upper end of the hydraulic oil chamber
  • the inner elastic film is disposed between the hydraulic oil chamber and the cavity
  • a driving mechanism connected to the piston, wherein the external strain bridge, the internal strain bridge and the driving mechanism are electrically connected to the processor.
  • the drive mechanism includes a stepping motor and a connecting rod, and the piston is coupled to the stepping motor through the connecting rod.
  • the processor is a single chip microcomputer.
  • a side of the hydraulic oil chamber is provided with a pressurized chamber, and the pressurized chamber is in communication with the hydraulic oil chamber, and the cross section of the pressurized chamber is smaller than a cross section of the hydraulic oil chamber.
  • the piston is disposed in the pressurized chamber.
  • the processor is disposed within the cavity.
  • the invention has the beneficial effects that the driving mechanism drives the piston to control the oil pressure in the hydraulic oil chamber, and the oil pressure is used to balance the external earth pressure, so that the outer elastic film is always in a non-deformed state, and only the inner elastic film is deformed, so that The soil arching effect and the soil displacement are avoided, so that the liquid pressure measured by the inner elastic film is the earth pressure, and the measurement result is more accurate.
  • FIG. 1 is a schematic structural view of a zero strain earth pressure sensor of the present invention
  • FIG. 2 is a block diagram showing the operation of a zero strain earth pressure sensor of the present invention.
  • the present invention discloses a zero-strain earth pressure sensor, which comprises a casing 1, a processor 2, an outer elastic membrane 3, an inner elastic membrane 4, an external strain bridge 31, and an internal strain bridge. 41.
  • the piston 7 and the driving mechanism, the housing 1 is provided with a hydraulic oil chamber 5 and a cavity 6 disposed at a lower end of the hydraulic oil chamber 5, and the outer elastic film 3 is disposed at an upper end of the hydraulic oil chamber 5,
  • the inner elastic mold 4 is disposed between the hydraulic oil chamber 5 and the cavity 6, and the outer strain bridge 31 is disposed outside the outer casing a lower end of the elastic membrane 3,
  • the inner strain bridge 41 is disposed at a lower end of the inner elastic mold 4, the hydraulic oil chamber 5 is filled with hydraulic oil, and the piston 7 is connected to the drive, and the live
  • the plug 7 is placed in the hydraulic oil chamber 5, and the driving mechanism can squeeze hydraulic oil in the hydraulic oil chamber 5 through the piston 7, the external strain bridge 31, the internal strain
  • the driving mechanism includes a stepping motor 9 and a connecting rod 10, and the piston 7 is connected to the stepping motor 9 through the connecting rod 10.
  • the stepping motor 9 in this embodiment is a micro stepping motor, and the control is further controlled.
  • the drive mechanism is a drive cylinder that drives the piston 7 to move by driving the cylinder, as well as compressing the hydraulic oil.
  • a side of the hydraulic oil chamber 5 is provided with a pressurized chamber 8, the pressurized chamber 8 is in communication with the hydraulic oil chamber 5, and the other side of the pressurized chamber 8 is connected to a driving chamber.
  • a stepping motor 9 is disposed in the driving cavity, the pressing chamber 8 has a cross section smaller than a cross section of the hydraulic oil chamber 5, and the piston 7 is disposed in the pressing chamber 8, such that The extruded hydraulic oil in the pressure chamber 8 is easier to control and the extrusion pressure is more precise.
  • the processor 2 is a single chip microcomputer, which has good controllability, is more reliable, durable, and has low cost.
  • the processor 2 is disposed in the cavity.
  • the external strain bridge 31 is connected to the processor 2 via a wire a 11
  • the stepping motor 9 is connected to the processor 2 via a wire b 12
  • the internal strain bridge 41 is connected to the processor 2 via a wire c 13 .
  • the processor 2 is connected to the power source and the output of the signal through the wire d14.
  • the outer elastic film 3 When the earth pressure sensor is subjected to external earth pressure, the outer elastic film 3 generates strain, and the outer strain bridge 31 measures the strain and transmits the signal to the single chip microcomputer 2. If the strain signal is not zero or exceeds a preset threshold, The single chip microcomputer 2 will issue a work command to the stepping motor 9, and the stepping motor 9 pushes the piston 7 through the connecting rod 10 to squeeze the hydraulic oil until the outer elastic film 3 returns to the non-deformed state, so that the oil pressure in the hydraulic oil chamber 5 Balanced with the external earth pressure, the inner elastic film 4 is deformed under the action of the oil pressure, the internal strain bridge 41 measures the strain and transmits a signal to the single chip microcomputer 2, and the corresponding pressure of the signal is the measured earth pressure. .
  • the invention is based on the feedback control principle, the driving mechanism drives the piston to control the oil pressure in the hydraulic oil chamber, and the oil pressure is used to balance the external earth pressure, so that the outer elastic film 3 is always in a non-deformed state, and only the inner elastic film 4 is deformed. This avoids the soil arching effect and the soil The displacement is such that the liquid pressure measured by the inner elastic film 4 is the earth pressure, and the measurement result is more accurate.

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  • General Physics & Mathematics (AREA)
  • Physics & Mathematics (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Health & Medical Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Food Science & Technology (AREA)
  • Biochemistry (AREA)
  • Geology (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • Environmental & Geological Engineering (AREA)
  • Medicinal Chemistry (AREA)
  • Analytical Chemistry (AREA)
  • Remote Sensing (AREA)
  • General Health & Medical Sciences (AREA)
  • Immunology (AREA)
  • Pathology (AREA)
  • Force Measurement Appropriate To Specific Purposes (AREA)
  • Investigating Strength Of Materials By Application Of Mechanical Stress (AREA)
  • Measuring Fluid Pressure (AREA)

Abstract

一种零应变土压力传感器，包括壳体（1）、处理器（2）、外弹性膜（3）、内弹性膜（4）、与外弹性膜（3）连接的外应变桥路（31）、与内弹性膜（4）连接的内应变桥路（41），壳体（1）设有液压油腔（5）及设于液压油腔（5）下端的空腔（6），外弹性膜（3）设于液压油腔（5）上端，内弹性膜（4）设于液压油腔（5）与空腔（6）之间，还包括与液压油腔（5）连通的活塞（7）及与活塞（7）连接的驱动机构，外应变桥路（31）、内应变桥路（41）及驱动机构均与处理器（2）电性连接。传感器的有益效果是通过驱动机构驱动活塞（7）来控制液压油腔（5）内的油压，利用油压来平衡外部土压力，使外弹性膜（3）始终处于无变形状态，而只有内弹性膜（4）发生变形，这样避免了土拱效应和土体移位，从而使内弹性膜（4）测量到的液体压力即为土压力，测量结果更加准确。

Description

零应变土压力传感器 技术领域
本发明涉及土压力测量领域，尤其涉及一种零应变土压力传感器。
背景技术
零应变土压力传感器是用于现场土体地应力测量的一种测试工具，目前主要采用把非电量(压力)转化为电量的方法进行测试，零应变土压力传感器大多数情况下均需要将传感器结构体埋入土介质中,使传感器与土介质协调变形,测试量则主要是结构的变形(应变)，而主要转化的电量则包括电感、电容、电阻、频率、电荷等，因此零应变土压力传感器的主要形式包括压电式、振弦式、电感式、电容式、电阻式等。目前使用最广的是振弦式和电阻式，测试量分别为频率和电压。电阻式传感器的原理是利用金属丝(片)电阻与其结构变化的关系,将结构物理量转化为可测电量。振弦式传感器使钢弦与传感器结构协调变形,通过钢弦在电磁激励下的振荡感应弦上应力的大小。压电晶体传感器是一种较有前途的动态应力测试传感器，压电晶体是指在晶体某一特定面施加荷载可以在其垂直面上产生电荷,卸载后电荷即消失的一类晶体。
目前所使用的大部分零应变土压力传感器只有一个弹性膜，且弹性膜在测量过程中由于外部压力的变化产生变形，弹性膜的变形会引起土拱效应或土体位移，导致局部土压力发生变化，从而带来显著的测量误差，还有一种双膜式零应变土压力传感器，但是该传感器在测量过程中二次膜片变形的同时也会引起一次膜片的变形，因而不能完全消除土拱效应或土体位移，从而还使测量产生误差。
发明内容
为了解决现有技术中的问题，本发明提供了一种测量更准确的零应变土压力传感器。
本发明提供了一种零应变土压力传感器，包括壳体、处理器、外弹性膜、内弹性膜、与所述外弹性膜连接的外应变桥路、与所述内弹性膜连接的内应变桥路，所述壳体设有液压油腔及设于所述液压油腔 下端的空腔，所述外弹性膜设于所述液压油腔上端，所述内弹性膜设于所述液压油腔与所述空腔之间，还包括与所述液压油腔连通的活塞及与所述活塞连接的驱动机构，所述外应变桥路、与所述内应变桥路及驱动机构均与所述处理器电性连接。
作为本发明的进一步改进，驱动机构包括步进电机及连杆，所述活塞通过所述连杆与所述步进电机连接。
作为本发明的进一步改进，所述处理器为单片机。
作为本发明的进一步改进，所述液压油腔一侧设有加压腔，所述加压腔与所述液压油腔连通，所述加压腔横截面小于所述液压油腔的横截面，所述活塞设于所述加压腔内。
作为本发明的进一步改进，所述处理器设于所述空腔内。
本发明的有益效果是：通过驱动机构驱动活塞来控制液压油腔内的油压，利用油压来平衡外部土压力，使外弹性膜始终处于无变形状态，而只有内弹性膜发生变形，这样避免了土拱效应和土体移位，从而使内弹性膜测量到的液体压力即为土压力，测量结果更加准确。
附图说明
图1是本发明一种零应变土压力传感器的结构示意图；
图2是本发明一种零应变土压力传感器的工作原理框图。
具体实施方式
附图标记：1-壳体、2-处理器、3-外弹性膜、4-内弹性模、5-液压油腔6-空腔、7-活塞、8-加压腔、9-步进电机、10-连杆、11-导线a、12-导线b、13-导线c、14-导线d、31-外应变桥路、41-内应变桥路。
如图1、图2所示，本发明公开了一种零应变土压力传感器，包括壳体1、处理器2、外弹性膜3、内弹性膜4、外应变桥路31、内应变桥路41、活塞7及驱动机构，所述壳体1设有液压油腔5及设于所述液压油腔5下端的空腔6，所述外弹性膜3设于所述液压油腔5上端、且设于所述壳体1表面，直接与土壤接触，所述内弹性模4设于所述液压油腔5与所述空腔6之间，所述外应变桥路31设于所述外弹性膜3下端，所述内应变桥路41设于所述内弹性模4下端，所述液压油腔5内装满液压油，所述活塞7与所述驱动连接，所述活 塞7置于所述液压油腔5内，所述驱动机构能够通过活塞7挤压液压油腔5内的液压油，所述外应变桥路31、与所述内应变桥路41及驱动机构均与所述处理器2电性连接。
所述驱动机构包括步进电机9及连杆10，所述活塞7通过所述连杆10与所述步进电机9连接，本实施例中的步进电机9为微型步进电机，控制更加精准，一些事实例中，所述驱动机构为驱动气缸，通过驱动气缸驱动所述活塞7运动，同样也能够起到压缩液压油的作用。
本实施例中，所述液压油腔5一侧设有加压腔8，所述加压腔8与所述液压油腔5连通，所述加压腔8另一侧连通有驱动腔，所述步进电机9置于所述驱动腔内，所述加压腔8横截面小于所述液压油腔5的横截面，所述活塞7设于所述加压腔8内，这样通过在加压腔8内的挤压液压油，更加容易控制，挤压压力更加精准。
本实施例中，所述处理器2为单片机，其控制性好、更加可靠、耐用而且成本较低。
本实施例中，所述处理器2设于所述空腔内。
所述外应变桥路31与处理器2通过导线a 11连接，所述步进电机9与处理器2通过导线b 12连接，所述内应变桥路41与处理器2通过导线c 13连接，所述处理器2通过到导线d 14与电源连接及信号的输出。
当土压传感器受到外部土压力作用时，外弹性膜3产生应变，外应变桥路31测量到应变并将信号传给单片机2，如果应变信号不为零或是超过预先设定的阀值，单片机2将给步进电机9发出工作指令，步进电机9通过连杆10推动活塞7移动从而挤压液压油，直至外弹性膜3恢复到无变形状态，这样液压油腔5内的油压与外部土压力保持平衡，此时内弹性膜4在油压的作用下发生变形，内应变桥路41测量到应变并将信号传给单片机2，该信号对应的压力即为测量到的土压力。
本发明基于反馈控制原理，通过驱动机构驱动活塞来控制液压油腔内的油压，利用油压来平衡外部土压力，使外弹性膜3始终处于无变形状态，而只有内弹性膜4发生变形，这样避免了土拱效应和土体 移位，从而使内弹性膜4测量到的液体压力即为土压力，测量结果更加准确。
以上内容是结合具体的优选实施方式对本发明所作的进一步详细说明，不能认定本发明的具体实施只局限于这些说明。对于本发明所属技术领域的普通技术人员来说，在不脱离本发明构思的前提下，还可以做出若干简单推演或替换，都应当视为属于本发明的保护范围。

Claims (5)

  1. 一种零应变土压力传感器，其特征在于：包括壳体、处理器、外弹性膜、内弹性膜、与所述外弹性膜连接的外应变桥路、与所述内弹性膜连接的内应变桥路，所述壳体设有液压油腔及设于所述液压油腔下端的空腔，所述外弹性膜设于所述液压油腔上端，所述内弹性膜设于所述液压油腔与所述空腔之间，还包括与所述液压油腔连通的活塞及与所述活塞连接的驱动机构，所述外应变桥路、与所述内应变桥路及驱动机构均与所述处理器电性连接。
  2. 根据权利要求1所述的零应变土压力传感器，其特征在于：驱动机构包括步进电机及连杆，所述活塞通过所述连杆与所述步进电机连接。
  3. 根据权利要求1所述的零应变土压力传感器，其特征在于：所述处理器为单片机。
  4. 根据权利要求1所述的零应变土压力传感器，其特征在于：所述液压油腔一侧设有加压腔，所述加压腔与所述液压油腔连通，所述加压腔横截面小于所述液压油腔的横截面，所述活塞设于所述加压腔内。
  5. 根据权利要求1所述的零应变土压力传感器，其特征在于：所述处理器设于所述空腔内。
PCT/CN2016/077926 2015-11-20 2016-03-30 零应变土压力传感器 Ceased WO2017084232A1 (zh)

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US15/771,386 US10451492B2 (en) 2015-11-20 2016-03-30 Zero-strain soil pressure sensor

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CN201510810591.3A CN105300570B (zh) 2015-11-20 2015-11-20 零应变土压力传感器

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CN111442992A (zh) * 2020-06-04 2020-07-24 天津城建大学 非饱和土三维应力状态动态测试装置及其实施方法

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CN105300570B (zh) 2015-11-20 2018-02-27 深圳大学 零应变土压力传感器
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CN115343448B (zh) * 2022-10-18 2023-03-17 湖南大学 一种基于土拱效应研究的新型活动门模型试验装置及方法
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