CN200989770Y - Sleeve type hole drilling multipoint extension meter - Google Patents

Abstract

The utility model discloses a casing type drilling multi-point extensometer used for measuring the loose deformation of surrounding rock in tunnels, which can accurately measure the displacements of multiple different depths. It includes an extension rod and at least one layer of extension tubes that are vacantly sleeved on the extension rod. One end of the extension rod and the extension tube extending into the measurement hole is fixed with a cemented charge. The positions of the points correspond to each other; the other end of the extension rod and the extension pipe extends to the opening of the measurement hole, so that multiple displacement monitoring at different depths can be concentrated in one borehole, which greatly simplifies the on-site operation and has environmental protection The utility model has the characteristics of good adaptability, simple operation, high measurement accuracy, low cost, and general personnel can operate with a little guidance, and is especially suitable for popularization and use in the existing loose deformation measurement of surrounding rock in tunnels.

Description

Casing type drilling multi-point extensometer

technical field

The utility model relates to a measuring device, in particular to a casing type drilling multi-point extensometer used for measuring loose deformation of surrounding rock in tunnels.

Background technique

Tunnel monitoring occupies an important position in tunnel engineering. Tunnel monitoring and measurement is to use various instruments and measuring equipment to measure various displacements and stresses of the tunnel during the tunnel excavation process. Due to its own particularity, the on-site monitoring of the tunnel has a special and important role, which is as important as the static calculation of the steel structure and concrete structure. After the tunnel is excavated, the original stress field of the surrounding rock is destroyed, and the stress state changes, breaking the stress balance state before excavation. The surrounding rock will reach a new balance through deformation and stress adjustment. . This adjustment is a dynamic process, so the deformation of the surrounding rock is also a dynamic process. The displacement of each point inside the surrounding rock is the dynamic performance of the deformation of the surrounding rock. It can reflect the degree of relaxation inside the surrounding rock and the size of the relaxation range. An important parameter index of the stability of the surrounding rock, the deformation trend of the surrounding rock is grasped through the dynamic information of the deformation of the surrounding rock, that is, the displacement-time curve is obtained from the measurement, and the change trend of the total displacement, displacement velocity and displacement acceleration at each time To analyze, so as to grasp the deformation state of surrounding rock. Generally speaking, the deformation gradually decreases from the cave wall to the deep part of the surrounding rock, and the deformation gradually tends to be stable with the increase of time. Therefore, it is possible to track and monitor the radial displacement at different depths of the rock around the cave, find out the location of sudden displacement at different depths, and determine the time when the displacement tends to be stable at the same depth, so as to predict the large deformation of the surrounding rock and determine the appropriate support time.

Tunnel construction itself has a certain complexity, and there is no very perfect instrument for its deformation monitoring. Its own characteristics also have certain requirements for tunnel monitoring instruments. In summary, there are the following points: 1. The equipment requires high precision; 2. High requirements for automation; 3. Strong environmental adaptability; 4. Strong operability. There are currently two main methods for measuring the looseness and deformation of tunnel surrounding rock. One is to measure only the out-of-plane displacement of the tunnel wall. The displacement at different depths is measured by a multi-point displacement meter for drilling.

The multi-point displacement meter is used to measure the relative displacement of different parts of the deep rock mass, or the absolute displacement relative to a certain reference point. The multi-point displacement value is obtained directly from the measurement results. Therefore, the measured value cannot directly reflect the displacement of each point in the deep surrounding rock. The deeper the surrounding rock is, the smaller the absolute displacement should be. Therefore, when the borehole is deep, the displacement of the measuring point at the bottom of the hole can be approximately considered to be zero or negligible. In this way, using the relative displacement value can more intuitively reflect the displacement of each point in the deep surrounding rock than the direct measurement value. The basic principle is: drill holes in different directions (generally along the normal direction of the cave wall) along the cave wall to the deep part of the surrounding rock, and use multi-point displacement meters to bury them in the borehole to form a series of measuring points. The displacement of the rock at the measuring point is transmitted to the bore hole through the steel wire or metal guide rod drawn from the measuring point, and the relative displacement from the anchor point to the hole is observed, so as to calculate the displacement distribution of the anchor measuring point along the axis of the borehole. Use electrical measurement method or mechanical meter measurement method for measurement. The embedding methods of multi-point displacement gauges can be divided into pre-buried before excavation and in-situ burial during excavation. The pre-buried multi-point displacement gauges must be at least twice the maximum characteristic of the cavern section before excavation to the observation section. Dimension distance has been buried, and began to take initial readings. If the instrument is buried now, the instrument should be as close as possible to the face of the tunnel, because after the excavation starts, the surrounding rock will quickly release the stress and deformation will also occur rapidly, and the anchorage measuring points in the same borehole should be arranged in the range with a large displacement gradient Inside. The results measured by the multi-point displacement meter can include: the relationship between the displacement of each measuring point and time, the relationship between the displacement of each measuring point and the excavation footage, the displacement change and distribution of the azimuth along the axis in the borehole, and the distribution of this form. The measured data are very helpful and meaningful for selecting the displacement back analysis model.

There are two types of multi-point displacement gauges: sensor type and mechanical type. The sensor type has high cost and poor stability, and cannot be used for long-term monitoring and mass use. The mechanical type mainly uses a rod-type multi-point displacement meter, and its main defects lie in two aspects: (1) It adopts full-hole cementation, and the displacement at each depth sometimes interferes with each other, which distorts the measurement results. The effect of is very significant, especially in weak rock mass. Generally, when full-length grouting is used, the reinforcement effect of mortar on the surrounding rock must be fully considered when analyzing the measured data, especially in soft rock. However, how much influence does this reinforcement effect have? Can rely on experience to make judgments. (2) The cost of raw materials and processing of the rod-type multi-point displacement meter is relatively high, so the application cost is relatively high, which is not conducive to popularization and use.

Utility model content

The technical problem to be solved by the utility model is to provide a casing-type drilling multi-point extensometer capable of accurately measuring displacements of multiple different depths.

The technical solution adopted by the utility model to solve the technical problem is: casing type drilling multi-point extensometer, which is characterized in that: it includes an extension rod and at least one layer of extension tubes that are empty on the extension rod, and the extension tubes are layer by layer. The number of tubes is determined according to the number of measuring points at different depths; the end of the extension rod and the extension tube extending into the measurement hole is fixed with a cemented charge, and the cemented charge on the extension rod and the layer-by-layer extension tube is along the bottom of the monitoring hole. The holes are arranged at intervals in sequence, the axial position of each cemented charge corresponds to the position of each measuring point in the measuring hole, and the other end of the extension rod and the extension tube extends to the orifice of the measuring hole. Using measuring tools such as dial indicators, it is convenient to measure the end of the extension rod and the extension tube at the position of the orifice, so as to easily measure the relative displacement or absolute displacement of the extension rod and the extension tube at different depths. displacement.

In order to better determine the position of the cemented drug pack, the extension rod and the extension tube extend into the side of the measurement hole and fix the fixed chuck. The outer diameter of the fixed chuck is slightly smaller than the aperture of the measurement hole, making it convenient Enter the measuring hole without interference, and the cemented drug pack is set at the fixed chuck.

In order to facilitate the installation, it is convenient to bond and fix the cemented drug package with the hole wall of the measuring hole after the extension rod or extension tube reaches the desired position, so as to prevent the position of the cemented drug package from moving during installation. A movable chuck with an outer diameter slightly smaller than the aperture of the measuring hole is sleeved on the rod and the extension pipe, and a space for installing a cemented drug package is formed between the fixed chuck and the movable chuck. The movable chuck is pushed axially by an external force, and the cemented drug package can be conveniently and accurately fixed on the hole wall of the measuring hole after being squeezed.

In order to facilitate the installation, the fixed chuck is set at the end of the extension rod and the extension tube, and the jacking tube is set between the adjacent cemented charges, and the jacking tube is sleeved on the corresponding extension rod or extension tube. The two ends are respectively in contact with the fixed chuck and the movable chuck of the adjacent cemented drug pack.

The beneficial effects of the utility model are: after adopting the above-mentioned technical scheme, it can be ensured that the anchored drug bag only acts on the position that needs to be fixed, and the extension rod and each extension tube form a small area of firm contact with the rock mass through the cemented drug bag. This segmented cementing method enables the loose displacement of the surrounding rock of the tunnel to be measured completely independently at each depth, and the measurement results are accurate and reliable, which reduces the influence of the experimental instrument itself on the rock displacement results, and multiple Displacement monitoring at different depths is concentrated in one borehole, which greatly simplifies the complexity of on-site operations, and the direct measurement of the surrounding rock deformation makes the measurement more accurate. It has the characteristics of good environmental adaptability, simple operation, high measurement accuracy, low cost, and general personnel can operate with a little guidance. In the tunnel environment where the construction conditions are relatively harsh, it can save time and workload, and it is easy to get the cooperation of the construction unit. The protection of the instrument is also very easy. A small protective cover is added outside, which has a very small area and is not easy to be damaged. It is especially suitable for popularization and use in the measurement of loose deformation of existing tunnel surrounding rocks.

Description of drawings

Fig. 1 is a schematic cross-sectional view in the horizontal direction of the installation structure of the present invention.

The marks in the figure are: measuring head 1, extension tube 2, extension rod 3, fixed chuck 4, movable chuck 5, jacking tube 6, socket 10, cemented drug pack 11, measuring hole 20, bottom 21, orifice twenty two.

Detailed ways

Below in conjunction with accompanying drawing and embodiment the utility model is further described.

As shown in Figure 1, the casing type drilling multi-point extensometer of the present utility model comprises an extension rod 3 and at least one layer of extension pipe 2 which is empty on the extension rod 3, and the extension rod 3 and the extension pipe 2 are used as the The deformation of the corresponding depth in the hole 20 is transmitted to the transfer rod for measurement at the orifice 22, and the extension tube 2 is empty on the extension rod 3 so that the axial movement is not affected by the extension rod 3; for the same reason, The multi-layer extension tubes 2 are also spaced apart from each other, that is, the large-diameter extension tubes 2 are spaced on the small-diameter extension tubes 2, so that the mutual axial movement is not affected. The length of the extension rod 3 is adapted to the depth of the measuring hole 20. One end of the extension rod 3 and the extension tube 2 extending into the measuring hole 20 is fixed with a cementing charge 11, which can be conventionally used in rock anchoring projects. Anchoring agent (anchor kit). The cementing charges 11 on the extension rod 3 and the layer-by-layer extension pipe 2 are arranged at intervals along the bottom 21 of the monitoring hole 20 to the orifice 22. The positions of each measuring point within 20 correspond to each other. The other end of the extension rod 3 and the extension pipe 2 extends to the opening 22 of the measuring hole 20, which is convenient for measuring the ends of the extension rod 3 and the extension pipe 2 after installation. The measurement can be carried out by using an electronic dial indicator, etc. The extension and contraction of the top ends of the extension rod 3 and the extension pipe 2 are used to measure and read the displacement of the surrounding rock, so as to realize the measurement of the loose deformation at different depths in the surrounding rock of the tunnel.

In order to ensure that the cemented drug pack 11 is fixed in the accurate position in the measuring hole 20 during installation, a fixed chuck 4 is fixedly arranged on the side where the extension rod 3 and the extension tube 2 extend into the measuring hole 20, and the fixed chuck 4 The outer diameter is slightly smaller than the diameter of the measuring hole 20 , and the cemented drug pack 11 is arranged at the fixed chuck 4 . The fixed chuck 4 plays the role of positioning the position of the cemented drug pack 11. When installing, push the cemented drug pack 11 with an external force to allow it to be close to the fixed chuck 4.

In order to facilitate installation, the extension rod 3 and the extension tube 2 are covered with a movable chuck 5 whose outer diameter is slightly smaller than the diameter of the measuring hole 20. A space is formed between the disk 4 and the movable chuck 5 for installing and cementing the drug pack 11 . During installation, pushing the movable chuck 5 with an external force can push the cementing drug pack 11 to the inner wall of the measuring hole 20 in an appropriate amount, so that it is well bonded on the inner wall of the measuring hole 20 .

In order to reduce the installation process and facilitate the installation better, the fixed chuck 4 can be fixed on the ends of the extension rod 3 and the extension pipe 2, and a jacking pipe 6 is arranged between adjacent cemented drug packs 11, and the jacking pipe 6 is empty. Sleeved on the corresponding extension rod 3 or extension pipe 2, the two ends of the jacking pipe 6 are in contact with the fixed chuck 4 and the movable chuck 5 of the adjacent cemented drug pack 11 respectively. In this way, when installing, the extension pipe 2 installed in the back can utilize the fixed chuck 4 at its end to push the jacking pipe 6 to extrude the extension rod 3 installed in the front or the movable chuck 5 on the extension pipe 2 when loading. Squeeze the bonding drug pack 11 to make the bonding position between the bonding drug pack 11 and the hole wall of the measuring hole 20 accurate and firm.

In order to facilitate measurement and manufacture, and reduce production costs, the extension rod 3 and the extension tube 2 extend to one end of the orifice 22 of the measurement hole 20, which is substantially flush, and the length of the extension rod 3 and the extension tube 2 is the same as that of each measuring point in the measurement hole 20. corresponding to the depth.

In order to ensure the accuracy of the measurement, the probe 1 can be fixedly installed at the orifice 22, and the outer end surface of the probe 1 is provided with a socket 10. The diameter of the socket 10 is smaller than the diameter of the corresponding extension rod 3 and the wall of the extension tube 2. Thickness, so that when measuring with a dial gauge, etc., it can be guaranteed that there will be no offset, thereby ensuring the accuracy of its measurement results.

The casing-type drilling multi-point extensometer of the utility model utilizes the characteristic that the temperature in the tunnel hole wall is relatively stable, and the main raw materials are materials that must be used in tunnel construction, which can greatly reduce the measurement cost. Extension bar 3 can adopt steel bar to make, and extension pipe 2 can adopt steel pipe to make, and jacking pipe 6 can adopt PVC plastic pipe to make.

The aforementioned empty sleeve means that the outer diameters of the extension tube 2 and the extension rod 3 are about smaller than the inner diameters of the extension tube 2 and the jacking tube 6 on which the extension tube 2 and the jacking tube 6 are fitted, so that the diameter of the extension tube 2 and the jacking tube 6 are set on it. The axial direction is supported to a certain extent, and the axial direction is not constrained by it, so that the bonding points of the extension pipe 2 and the extension rod 3 are firmly bonded to the rock mass, and the deep deformation of the rock is better introduced to the outside for measurement.

It can be seen from the above that the extension rod 3 and the extension pipe 2 as transmission rods can move freely in a small range in the axial direction except that the end points are in firm contact with the surrounding rock. The jacking pipe 6 made of PVC pipe can not only ensure that the position of the anchor point is exactly the design depth, but also effectively reduce the contact between the transmission rod and the hole wall, and reduce the influence of frictional resistance on the measurement results.

Claims (5)

1, sleeve bore multidot tensiometer, it is characterized in that: comprise that bar of extending (3) and sky are enclosed within the extension tube of one deck at least (2) on the bar of extending (3), the end that bar (3) and extension tube (2) stretch into measured hole (20) of extending is fixed with cementation cartridge bag (11), extend bar (3) and successively the cementation cartridge bag (11) on the extension tube of suit (2) along the bottom (21) of monitoring holes (20) to the aperture (22) sequence interval arrange, the axial location of each cementation cartridge bag (11) is corresponding with the position of each measuring point in the measured hole (20), and the other end of bar of extending (3) and extension tube (2) extends to the aperture (22) of measured hole (20).

2, sleeve bore multidot tensiometer as claimed in claim 1, it is characterized in that: the end that bar of extending (3) and extension tube (2) stretch into measured hole (20) is set with fixedly chuck (4), fixedly the external diameter of chuck (4) is slightly less than the aperture of measured hole (20), and cementation cartridge bag (11) is arranged on fixedly chuck (4) and locates.

3, sleeve bore multidot tensiometer as claimed in claim 2, it is characterized in that: be set with the movable chuck (5) that external diameter is slightly less than the aperture of measured hole (20) on bar of extending (3) and the extension tube (2), fixedly form the space that cementation cartridge bag (11) is installed between chuck (4) and the movable chuck (5).

4, sleeve bore multidot tensiometer as claimed in claim 3, it is characterized in that: fixedly chuck (4) is arranged on the end of bar of extending (3) and extension tube (2), be provided with push pipe (6) between the adjacent cementation cartridge bag (11), push pipe (6) sky is enclosed within on bar of extending accordingly (3) or the extension tube (2), and the two ends of push pipe (6) contact with movable chuck (5) with the fixedly chuck (4) of adjacent cementation cartridge bag (11) respectively.

5, according to any described sleeve bore multidot tensiometer of claim in the claim 1～4, it is characterized in that: the end group that bar of extending (3) and extension tube (2) extend the aperture (22) of measured hole (20) originally flushes, and the length of bar of extending (3) and extension tube (2) is corresponding with each measuring point degree of depth in the measured hole (20).

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