CN212772499U - Foundation ditch fender pile horizontal displacement's measuring device - Google Patents

Foundation ditch fender pile horizontal displacement's measuring device Download PDF

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Publication number
CN212772499U
CN212772499U CN202020724915.8U CN202020724915U CN212772499U CN 212772499 U CN212772499 U CN 212772499U CN 202020724915 U CN202020724915 U CN 202020724915U CN 212772499 U CN212772499 U CN 212772499U
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measuring
metal rod
horizontal displacement
strain gauge
foundation pit
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CN202020724915.8U
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Chinese (zh)
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张�杰
江凡
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Fujian Gongda Geotechnical Engineering Research Institute Co ltd
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Fujian Gongda Geotechnical Engineering Research Institute Co ltd
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Abstract

The utility model provides a foundation ditch fender pile horizontal displacement's measuring device, include: the metal rod is provided with one measuring surface every other length unit along the length direction; the strain gauge is attached to the measuring surface; four strain gauges are arranged around each measuring surface and are distributed at equal intervals; the strain gauge is electrically connected with each strain gauge; the displacement and corner monitor can monitor the horizontal displacement and the corner of the top end of the metal rod; the metal rod is used for being embedded in the foundation pit support pile, and the top end of the metal rod is exposed out of the upper surface of the foundation pit support pile. The utility model has the advantages that: the utility model discloses only need paste at every survey face of metal pole and establish four foil gauges, according to the dependent variable that foil gauge generated when metal pole is crooked, calculate the stress that corresponds the position, utilize the amount of deflection when stress calculation metal pole is crooked to reflect the horizontal displacement that the foundation ditch fender pile of slope produced.

Description

Foundation ditch fender pile horizontal displacement's measuring device
[ technical field ] A method for producing a semiconductor device
The utility model relates to a building engineering monitoring technology field specifically relates to a foundation ditch fender pile horizontal displacement's measuring device.
[ background of the invention ]
The foundation pit support is a retaining, reinforcing and protecting measure adopted for the side wall of the foundation pit and the surrounding environment in order to ensure the safety of the construction of an underground structure and the surrounding environment of the foundation pit. Common foundation pit supporting forms mainly include: 1. pile support, pile anchor and pile cantilever; 2. supporting an underground continuous wall, and supporting the underground continuous wall; 3. cement retaining walls, and the like. The foundation pit supporting pile may incline in the using process, and the inclination degree of the foundation pit supporting pile is indicated by monitoring the horizontal displacement generated by the inclined foundation pit supporting pile.
Conventional patent document 1: the name "a method for improving the accuracy of an azimuth angle and a tool face angle of a fiber optic gyro inclinometer for small well inclinations", publication No. CN103104251A, discloses the use of an attitude angle relationship between an azimuth angle and a tool face angle for monitoring the inclination degree. Prior patent document 2: the name of a linear fixed wireless deep hole inclinometer and a deep hole inclination measuring system is published with No. CN103498665A, and the horizontal displacement is calculated by the inclination of each measuring hole. The existing monitoring mode mainly has the following problems: 1. the gyro inclinometer may slide in the sleeve to affect monitoring; 2. each measuring hole needs to be provided with an element for monitoring the inclination, and the price is high.
[ Utility model ] content
The to-be-solved technical problem of the utility model lies in providing a foundation ditch fender pile horizontal displacement's measuring device, can measure firmly steadily.
The utility model discloses a realize like this:
a foundation ditch fender pile horizontal displacement's measuring device includes:
the metal rod is provided with one measuring surface every other length unit along the length direction;
the strain gauge is attached to the measuring surface; four strain gauges are arranged around each measuring surface and are distributed at equal intervals;
the strain gauge is electrically connected with each strain gauge;
the displacement and corner monitor can monitor the horizontal displacement and the corner of the top end of the metal rod;
the metal rod is used for being embedded in the foundation pit support pile, and the top end of the metal rod is exposed out of the upper surface of the foundation pit support pile.
Further, the measuring surfaces are marked every other meter along the length direction of the metal rod.
Furthermore, each strain gauge is provided with a lead, each lead is led out upwards along the rod body of the metal rod, and the other end of each lead is connected with the strain gauge.
Further, still include the computer, the computer with the strain gauge, displacement corner monitor electricity is connected.
The utility model has the advantages that: the utility model only needs to stick four strain gauges on each side of the metal rod, calculates the stress of the corresponding position according to the strain generated by the strain gauges when the metal rod is bent, and calculates the deflection of the metal rod when the metal rod is bent by utilizing the stress, thereby reflecting the horizontal displacement generated by the inclined foundation pit support pile; the strain gauge is fixed on the metal rod and cannot slide; need arrange the component of special monitoring gradient such as gyro inclinometer specially in the measurement mode with present and compare, the technical scheme of the utility model cost is lower, measures more stably.
[ description of the drawings ]
The invention will be further described with reference to the following examples with reference to the accompanying drawings.
Fig. 1 is a schematic structural diagram of the utility model with a metal rod embedded in a foundation pit support pile.
Fig. 2 is a schematic view of the measuring surface of the present invention along the length direction of the metal rod.
Fig. 3 is a schematic diagram of the arrangement of the middle strain gauge surrounding the measuring surface.
Fig. 4 is the utility model discloses well foundation ditch fender pile and metal pole take place the sketch map of slope.
Fig. 5 is a schematic view of measuring point stress analysis of the middle measuring surface of the present invention.
Fig. 6 is a schematic block diagram of the device for measuring horizontal displacement of the foundation pit support pile of the present invention.
Fig. 7 is a flow chart of a specific usage of the measuring device of the present invention.
Reference numerals: a metal rod 100; a metal rod 101; a strain gage 200; measuring the surface 300; foundation pit supporting piles 400; a strain gauge 500; a displacement rotation angle monitor 600; a computer 700.
[ detailed description ] embodiments
The embodiment of the utility model provides a through providing a foundation ditch fender pile horizontal displacement's measuring device, solved and measured unstable technical problem among the prior art, realized measuring stable with low costs's technological effect.
The embodiment of the utility model provides an in technical scheme for solving above-mentioned problem, the general thinking is as follows: four strain gauges are attached to each side face of the metal rod, stress of corresponding positions is calculated according to strain generated by the strain gauges when the metal rod is bent, deflection of the metal rod when the metal rod is bent is calculated by means of the stress, and the metal rod is embedded in the foundation pit supporting pile, so that horizontal displacement generated by the inclined foundation pit supporting pile is reflected.
For better understanding of the above technical solutions, the following detailed descriptions will be provided in conjunction with the drawings and the detailed description of the embodiments.
Referring to fig. 1 to 7, the present invention provides a preferred embodiment of a device for measuring horizontal displacement of a foundation pit support pile.
The utility model discloses a measuring device, include:
a metal bar 100 having a measuring surface 300 marked every other length unit along a length direction thereof; in this embodiment, the measuring surface 300 is marked every other meter, the shaft of the metal rod 100 is cylindrical, and the measuring surface 300 is represented as a cross section of the metal rod 100.
The strain gauge 200 is attached to the measuring surface 300; each measuring surface 300 is provided with four strain gauges 200 in a surrounding manner and distributed at even intervals to form four measuring points, namely, connecting lines between the adjacent two strain gauges 200 and the circle center of the measuring surface 300 are in a vertical relationship.
A strain gauge 500 electrically connected to each of the strain gauges 200; each strain gauge 200 is provided with a lead wire, each lead wire is led out upwards along the shaft of the metal rod 100, and the other end of each lead wire is connected with the strain gauge 500. The strain gauge 500 employs a static strain test system model DH 3816.
The displacement and rotation angle monitor 600 can monitor the horizontal displacement and rotation angle of the top end 101 of the metal rod 100; the displacement rotation angle monitor 600 may utilize GNSS technology, which is a global navigation satellite system, such as the zhonghaida V98 GNSS RTK system. The displacement and rotation angle monitor can also comprise an inclinometer and a total station; the inclinometer is an ACE5411 portable digital inclinometer and is used for measuring the top corner of the metal rod; the total station selects STS-772 series win total stations for measuring the top horizontal displacement of the metal rod.
The metal rod 100 is embedded in the foundation pit support pile 400, and the top end 101 of the metal rod 100 is exposed out of the upper surface of the foundation pit support pile 400. The strain gauge 500 and the displacement and rotation angle monitor 600 are both installed above the foundation pit support pile 400.
The strain gauge further comprises a computer 700, wherein the computer 700 is electrically connected with the strain gauge 500 and the displacement and rotation angle monitor 600.
If the foundation pit support piles 400 are inclined, the built-in metal bars 100 are bent by the inclination. The four strain gauges 200 on each side surface 300 of the bent metal rod 100 generate corresponding strains, the strain gauge 500 collects the strain values of the respective strain gauges 200, and the strain gauge 500 transmits the collected strain data to the computer 700. The displacement and rotation angle monitor 600 collects the horizontal displacement and rotation angle of the top end 101 of the metal rod 100, and the displacement and rotation angle monitor 600 transmits the collected displacement and rotation angle data to the computer 700. The computer 700 calculates the horizontal displacement of each measuring surface 300 on the metal rod 100 at this time according to a preset formula, reflects the horizontal displacement of the foundation pit support pile 400, and finally displays the result on the screen by the computer 700.
The utility model discloses a measuring device concrete use mode:
s10, marking a measuring surface 300 every other length unit along the length direction of the metal rod 100; in this embodiment, the measuring surface 300 is marked every other meter, the shaft of the metal rod 100 is cylindrical, and the measuring surface 300 is represented as a cross section of the metal rod 100.
S20, four strain gauges 200 are attached to each measuring surface 300 in a surrounding mode, and the four strain gauges 200 are evenly distributed at intervals; four measuring points are formed, namely, the connecting lines of the adjacent two strain gauges 200 to the circle center of the measuring surface 300 are in a vertical relation.
S30, embedding the metal rod 100 in a foundation pit support pile 400, wherein the top end 101 of the metal rod 100 is exposed out of the upper surface of the foundation pit support pile 400; thus, if the foundation pit support piles 400 are inclined, the metal bars 100 are inclined to be bent.
Each strain gauge 200 is provided with a lead wire, each lead wire is led out upwards along the shaft of the metal rod 100, and the other end of each lead wire is connected with a strain gauge 500. The strain gauge 500 employs a static strain test system model DH 3816. The upper surface mounting of fender pile has displacement corner monitor 600, displacement corner monitor 600 can monitor the top 101 horizontal displacement and the corner of metal pole 100. The displacement rotation angle monitor 600 may utilize GNSS technology, which is a global navigation satellite system, such as the zhonghaida V98 GNSS RTK system. The displacement and rotation angle monitor can also comprise an inclinometer and a total station; the inclinometer is an ACE5411 portable digital inclinometer and is used for measuring the top corner of the metal rod; the total station selects STS-772 series win total stations for measuring the top horizontal displacement of the metal rod.
S40, monitoring the horizontal displacement and the rotation angle of the top end 101 of the metal rod 100, and collecting the strain of each strain gauge 200; these data are recorded.
S50, calculating to obtain the horizontal displacement of each measuring surface 300 on the metal rod 100; each side surface 300 of the bent metal rod 100 corresponds to a position of the foundation pit support pile 400, thereby obtaining a horizontal displacement of the foundation pit support pile 400. Stably monitoring the inclination degree of the foundation pit support piles 400; the strain gauge 200 is attached to the metal rod 100 and embedded in the foundation pit support pile 400, so that the strain gauge 200 cannot slide, and the measurement accuracy is improved.
The calculation process specifically comprises the following steps:
the strain values of four strain gauges which are at a distance of i length units from the top end of the metal rod are sequentially epsiloni1、εi2、εi3、εi4Wherein i is a positive integer; for example, the strains of four strain gauges one meter away from the top end of the metal rod are sequentially ε11、ε12、ε13、ε14(ii) a The strain of four strain gauges which are two meters away from the top end of the metal rod is sequentially epsilon21、ε22、ε23、ε24(ii) a And so on. When the metal rod is bent, whether the measuring point at the corresponding position of the metal rod is stretched or compressed can be known according to the strain amount of the strain gauge at the corresponding position.
The following formula refers to "material mechanics", and from formula (1), σ ═ E ∈, the stress value corresponding to the strain gauge position is obtained as: sigmai1、σi2、σi3、σi4Wherein E is the modulus of elasticity of the metal rod; that is, the stress of four measuring points of a measuring surface which is one meter away from the top end of the metal rod is sigma11、σ12、σ13、σ14(ii) a The stress of four measuring points of a measuring surface which is two meters away from the top end of the metal rod is sigma21、σ22、σ23、σ24(ii) a And so on. The stress values of four measuring points in the measuring surface of the bent metal rod are positive and represent tensile stress, and the stress values are negative and represent compressive stress.
As shown in FIG. 5, the four measurement points are labeled A, B, C, D respectively for a certain measurement surface, corresponding to a stress σi1、σi2、σi3、σi4(ii) a The circle center of the measuring surface is marked as O, the neutral axis of the measuring surface is marked as Z, the intersection point of the vertical connecting line from the measuring point A to the neutral axis Z is marked as E, and the intersection point of the vertical connecting line from the measuring point B to the neutral axis Z is marked as F. When the metal rod is bent, the stress sigma of the measuring point A is ideally measuredi1Stress sigma with measuring point Ci3Opposite numbers of each other, stress σ of point Bi2Stress sigma with measuring point Di4Are opposite numbers, but have deviation in practice, so the stress sigma of the measuring point A is determined by taking the average valueAAnd measuring point sigmaDI.e.:
since in fig. 5 Δ AEO and Δ DFO are equal, the length of DF is equal to the length of EO; according to the formula in Material mechanics:the calculation formula of the normal stress at any point on the cross section of the straight beam in pure bending is shown; wherein M is a bending moment, IZIs the moment of inertia, and y is the ordinate of the stress point; it can be seen that the stress at the location of a measurement point is directly proportional to the perpendicular distance of the measurement point from the neutral axis. The point of the circular cross-section of fig. 5 where the perpendicular distance to the neutral axis is greatest, i.e. equal to the radius of the circle, is the point where the stress is greatest, denoted G, and where the stress is denoted as σi,maxThe maximum tensile stress is indicated.
With reference to FIG. 5, then
Namely, it is
Equation (2) is obtained.
Calculating the maximum tensile stress value sigma of each measuring surface by the formula (2)i,max
Is prepared from formula (3)
Wherein M is a bending moment, IZIs the moment of inertia, y is the ordinate of the stress point, d is the cross-sectional diameter of the bending rod; calculating the bending moment M of each measuring surfaceiI.e. by
Approximating differential equations by flexible lines, i.e.
Equation (4) EIzω=-∫[∫M(x)dx]dx+C1x+C2Where ω is the cross-sectional deflection of the curved rod, i.e. horizontal displacement, IzIs moment of inertia, C1And C2Is a constant; the boundary condition is the horizontal displacement omega of the top end of the metal rod0Angle of rotation theta0Substituting the obtained bending moment discrete point of the measuring surface of each depth into the differential equation, and solving the differential equation of the discrete data by using the conventional MATLAB tool to calculate the horizontal displacement omega of each measuring surface on the metal rodi. This reflects the horizontal displacement of the foundation pit support piles.
Although specific embodiments of the present invention have been described, it will be understood by those skilled in the art that the specific embodiments described are illustrative only and are not limiting upon the scope of the invention, and that equivalent modifications and variations can be made by those skilled in the art without departing from the spirit of the invention, which is to be limited only by the claims appended hereto.

Claims (4)

1. The utility model provides a foundation ditch fender pile horizontal displacement's measuring device which characterized in that includes:
the metal rod is provided with one measuring surface every other length unit along the length direction;
the strain gauge is attached to the measuring surface; four strain gauges are arranged around each measuring surface and are distributed at equal intervals;
the strain gauge is electrically connected with each strain gauge;
the displacement and corner monitor can monitor the horizontal displacement and the corner of the top end of the metal rod;
the metal rod is used for being embedded in the foundation pit support pile, and the top end of the metal rod is exposed out of the upper surface of the foundation pit support pile.
2. The apparatus for measuring the horizontal displacement of a foundation pit support pile as claimed in claim 1, wherein said side surfaces are marked every other meter along the length of said metal rod.
3. The device for measuring the horizontal displacement of the foundation pit support pile as claimed in claim 1, wherein each strain gauge is provided with a lead, each lead is led out upwards along the rod body of the metal rod, and the other end of each lead is connected with the strain gauge.
4. The apparatus for measuring the horizontal displacement of a foundation pit support pile according to claim 1, further comprising a computer, wherein the computer is electrically connected to the strain gauge and the displacement and rotation angle monitor.
CN202020724915.8U 2020-05-06 2020-05-06 Foundation ditch fender pile horizontal displacement's measuring device Active CN212772499U (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202020724915.8U CN212772499U (en) 2020-05-06 2020-05-06 Foundation ditch fender pile horizontal displacement's measuring device

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202020724915.8U CN212772499U (en) 2020-05-06 2020-05-06 Foundation ditch fender pile horizontal displacement's measuring device

Publications (1)

Publication Number Publication Date
CN212772499U true CN212772499U (en) 2021-03-23

Family

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Family Applications (1)

Application Number Title Priority Date Filing Date
CN202020724915.8U Active CN212772499U (en) 2020-05-06 2020-05-06 Foundation ditch fender pile horizontal displacement's measuring device

Country Status (1)

Country Link
CN (1) CN212772499U (en)

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