Benchmark fixture for settlement monitoring

Abstract

The invention discloses a reference point fixing device for settlement monitoring, wherein the fixing rod comprises a drill bit, a plurality of hollow connecting rods and a grouting conduit, wherein the plurality of connecting rods are detachably connected end to end, the drill bit is fixedly connected to the bottom end of the connecting rod at the lowest end, and the connecting rod at the lowest end is provided with a grouting hole close to the drill bit, the grouting conduit passes through each connecting rod in turn and is connected to the grouting hole, the settlement plate is placed on the foundation surface and can move up and down along the connecting rod, and the displacement sensor can measure the descending depth of the settlement plate and is connected to the acquisition device. There is no need to drill holes in advance, thus saving construction costs, and the on-site construction is convenient, and the device can be used for automatic settlement monitoring of large-area soft foundation treatment.

Description

Technical Field

[0001] The invention relates to a reference point fixing device for settlement monitoring. Background Art

[0002] Land reclamation or soft soil area projects need to be treated to meet the requirements of subsequent engineering construction. Surface settlement observation is one of the monitoring items of soft foundation treatment projects. The purpose of soft foundation treatment is consolidation settlement. Surface settlement is the most direct reflection of the reinforcement effect. It is also the basis for controlling the loading rate, calculating the post-construction settlement and consolidation degree, and determines the speed of construction progress and the arrangement of later construction.

[0003] Traditional manual monitoring methods are often used for settlement monitoring. However, manual monitoring is time-consuming, labor-intensive, inefficient, requires a large and cumbersome workload, has poor observation accuracy, and cannot achieve automated real-time monitoring.

[0004] Automated monitoring can well solve the problems existing in manual monitoring, such as the Chinese patent application number 201910213113.2, the patent name is a patent for an automatic monitoring device for foundation settlement based on a laser ranging module, which includes an above-ground part and an underground part. The underground part includes a steel pipe pile driven into and stabilized in the foundation, a laser ranging module and a settlement plate, and the above-ground part includes a wireless data acquisition module and a data processing terminal. An equipment installation groove is excavated on the upper part of the foundation around the steel pipe pile, and the settlement plate is horizontally arranged at the bottom of the equipment installation groove. The laser ranging module is vertically arranged above the settlement plate. The laser ranging module is vertically fixed on one side of the steel pipe pile through a bracket. The bracket and the laser ranging module are installed in the equipment installation groove. The laser ranging module is provided with a laser rangefinder, a communication module, a flash memory card and a battery pack located at the bottom. The present invention can automatically monitor foundation settlement, does not require manual field measurement, can avoid manual measurement errors, the data is accurate and reliable, the monitoring cost is low, and it is convenient to conduct specific analysis of foundation settlement data. However, this automatic monitoring device does not provide how to fix the reference fixed point.

[0005] For large-scale soft foundation settlement automation monitoring, the determination of the benchmark fixed point directly determines the success or failure of the automated settlement monitoring. At present, the determination of the benchmark fixed point is done by drilling to the bedrock surface, and using the bedrock surface as the benchmark point for automated settlement monitoring. However, the drilling cost is high, especially for deep bedrock surfaces, which will greatly increase the construction cost. In addition, for some soft sites, large drilling machinery cannot enter the site, making construction difficult. Summary of the invention

[0006] The present invention provides a reference point fixing device for settlement monitoring, which overcomes the shortcomings of the background technology. The technical solution adopted by the present invention to solve its technical problem is:

[0007] A reference point fixing device for settlement monitoring, comprising a settlement plate, a fixing rod, a displacement sensor and a collection device, wherein the fixing rod comprises a drill bit, a plurality of hollow connecting rods and a grouting conduit, wherein the plurality of connecting rods are detachably connected end to end, wherein the drill bit is fixedly connected to the bottom end of the connecting rod at the lowest end, and the connecting rod at the lowest end is provided with a grouting hole close to the drill bit, wherein the grouting conduit passes through each connecting rod in turn and is connected to the grouting hole, wherein the settlement plate is placed on the foundation surface and can move up and down along the connecting rod, wherein the displacement sensor can measure the descending depth of the settlement plate and is connected to the collection device;

[0008] Drive the fixed rod into the soil until the drill bit moves to the theoretical reference point, and compare the negative friction f generated by the soil settlement above the reference point on the connecting rod. s and the end resistance f of the drill bit b If the size between b ≥f s , there is no need to grout the drill bit; if f b ≤f s , grouting operation is performed on the soil near the drill bit through the grouting conduit and the grouting hole to fix the drill bit;

[0009] Where: f is calculated using the empirical coefficient a s ,Right now Where πd is the circumference of the connecting rod, hi is the thickness of each layer of soil; according to f b =qπr 2 Calculate f b , where q is the empirical parameter of the end resistance, πr 2 is the drill bit surface area.

[0010] In a preferred embodiment: Calculation of the theoretical reference point depth:

[0011] ① Use the stress ratio method to calculate the soil self-weight stress distribution σ cz and additional stress distribution σ z , take σ z / σ cz = 0.2. If the soil below this depth is highly compressible, then σ z / σ cz =0.1 corresponding depth H; ② Use stress area method to calculate depth H, satisfying Δs' i is the calculated settlement of the i-th layer of soil within the calculation depth range, Δs' n To calculate the settlement, take a 1m thick soil layer at depth H; ③ Take the larger value of the depth calculated by the two methods. If there is bedrock within the depth range, take the depth at the bedrock surface as the reference point depth.

[0012] In a preferred embodiment: the top end and the bottom end of the connecting rod are respectively provided with a first fixing portion and a second fixing portion, and two adjacent connecting rods are fixedly connected by the fixed cooperation between the first fixing portion and the second fixing portion.

[0013] In a preferred embodiment: the top end of the drill bit is provided with a third fixing portion which can cooperate with the second fixing portion, and the connecting rod is fixedly connected to the drill bit through the fixed cooperation between the second fixing portion and the third fixing portion.

[0014] In a preferred embodiment: the first fixing portion and the third fixing portion are both internal threads, and the second fixing portion is an external thread; or, the first fixing portion and the third fixing portion are both external threads, and the second fixing portion is an internal thread.

[0015] In a preferred embodiment: the settlement plate includes a transverse plate and a vertical sleeve fixedly connected to the center of the transverse plate, the top end of the fixing rod passes through the transverse plate and extends into the vertical sleeve, and the displacement sensor and the acquisition device are both installed at the top end of the vertical sleeve.

[0016] In a preferred embodiment: the settlement plate further includes a reinforcing rib, which is arranged obliquely and has one end fixedly connected to the vertical sleeve and the other end fixedly connected to the top surface of the transverse plate.

[0017] In a preferred embodiment: the displacement sensor is a pull-wire sensor, and the bottom end of the pull-wire is connected to the top end of the fixed rod.

[0018] In a preferred embodiment: the grouting holes are provided in plurality and are spaced apart from each other.

[0019] In a preferred embodiment: the connecting rod is made of a rigid material.

[0020] Compared with the background technology, this technical solution has the following advantages:

[0021] 1. The fixing device only needs to drive the drill bit of the fixing rod to the depth of the theoretical reference point, and the negative friction f generated by the soil settlement above the reference point on the connecting rod s and the end resistance f of the drill bit b The size between the two can be used for grouting or not grouting. b ≥f s , there is no need to grout the drill bit; if f b ≤f s , grouting is performed on the soil near the drill bit through the grouting conduit and grouting hole to fix the drill bit. This type of fixing device can effectively fix the fixing rod, and the position of the fixing rod will not change with the influence of foundation settlement. The fixing rod has good stability. In addition, there is no need to drill holes in advance, which saves construction costs. At the same time, on-site construction is convenient, and it can be used for large-area soft foundation treatment settlement automatic monitoring.

[0022] 2. The theoretical reference point depth is calculated by comparing the reference point depth obtained by the stress ratio method and the reference point depth obtained by the stress area method and taking the larger value, so that the calculation of the theoretical reference point depth is more accurate. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0024] Figure 1 The overall schematic diagram of a reference point fixing device for settlement monitoring according to a preferred embodiment is shown. DETAILED DESCRIPTION

[0025] In the claims, description and the above-mentioned drawings of the present invention, unless otherwise clearly defined, the use of terms such as "first", "second" or "third" etc. are for distinguishing different objects rather than for describing a specific order.

[0026] In the claims, specification and the above-mentioned drawings of the present invention, unless otherwise explicitly defined, directional words, such as the terms "center", "lateral", "longitudinal", "horizontal", "vertical", "top", "bottom", "inside", "outside", "up", "down", "front", "back", "left", "right", "clockwise", "counterclockwise", etc., indicating directions or positional relationships are based on the directions and positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction or be constructed and operated in a specific direction, and therefore cannot be understood as limiting the specific protection scope of the present invention.

[0027] In the claims, specification and the above drawings of the present invention, unless otherwise clearly defined, the terms "fixed connection" and "fixed connection" should be understood in a broad sense, that is, any connection method without any displacement relationship and relative rotation relationship between the two parties, that is to say, including non-detachable fixed connection, detachable fixed connection, integral connection and fixed connection through other devices or elements.

[0028] In the claims, description and drawings of the present invention, if the terms "include", "have" and their variations are used, they are intended to mean "including but not limited to".

[0029] Please refer to Figure 1 A preferred embodiment of a reference point fixing device for settlement monitoring, the reference point fixing device for settlement monitoring includes a settlement plate, a fixing rod, a displacement sensor 7 and a collection device 8.

[0030] The fixing rod comprises a drill bit 1, a plurality of hollow connecting rods 2 and a grouting conduit 5. The plurality of connecting rods 2 are detachably connected end to end. The drill bit 1 is fixedly connected to the bottom end of the connecting rod 2 at the lowest end, and the connecting rod 2 at the lowest end is provided with a grouting hole 3 close to the drill bit 1. The grouting conduit 5 passes through each connecting rod 2 in turn and is connected to the grouting hole 3. The settlement plate is placed on the foundation surface and can move up and down along the connecting rod 2. The displacement sensor 7 can measure the descending depth of the settlement plate and is connected to the acquisition device 8.

[0031] Drive the fixed rod into the soil until the drill bit 1 moves to the theoretical reference point, and compare the negative friction f generated by the soil settlement above the reference point on the connecting rod. s and the end resistance f of the drill bit b If the size between b ≥f s , then there is no need to grout the drill bit 1; if f b ≤f s , grouting operation is performed on the soil near the drill bit 1 through the grouting conduit 5 and the grouting hole 3 to fix the drill bit 1;

[0032] Where: f is calculated using the empirical coefficient a s ,Right now Where πd is the circumference of connecting rod 2, hi is the thickness of each layer of soil; according to f b =qπr 2 Calculate f b , where q is the empirical parameter of the end resistance, πr 2 is the drill bit surface area.

[0033] In this embodiment, the calculation of the theoretical reference point depth is:

[0034] ① Use the stress ratio method to calculate the soil self-weight stress distribution σ cz and additional stress distribution σ z , take σ z / σ cz = 0.2. If the soil below this depth is highly compressible, then σ z / σ cz =0.1 corresponding depth H; ② Use stress area method to calculate depth H, satisfying Δs' i is the calculated settlement of the i-th layer of soil within the calculation depth range, Δs' n To calculate the settlement, take a 1m thick soil layer at depth H; ③ Take the larger value of the depth calculated by the two methods. If there is bedrock within the depth range, take the depth at the bedrock surface as the reference point depth.

[0035] In this embodiment, the top and bottom ends of the connecting rod 2 are respectively provided with a first fixing portion and a second fixing portion, and two adjacent connecting rods 2 are fixedly connected by the fixed cooperation of the first fixing portion and the second fixing portion. In addition, the top end of the drill bit 1 is provided with a third fixing portion that can cooperate with the second fixing portion, and the connecting rod 2 is fixedly connected to the drill bit 1 by the fixed cooperation between the second fixing portion and the third fixing portion.

[0036] Specifically, the first fixing portion and the third fixing portion are both internal threads 4, and the second fixing portion is an external thread 41; or, as required, the first fixing portion and the third fixing portion may also be external threads, and the second fixing portion may also be an internal thread.

[0037] In this embodiment, three grouting holes 3 are provided and arranged at intervals in the upper and lower parts. In addition, the connecting rod 2 is made of a rigid material.

[0038] In this embodiment, the sedimentation plate includes a transverse plate 6 and a vertical sleeve 61 fixed to the center of the transverse plate 6. The top end of the fixing rod passes through the transverse plate 6 and extends into the vertical sleeve 61. The displacement sensor 7 and the acquisition device 8 are both installed at the top end of the vertical sleeve 61.

[0039] In this embodiment, the settlement plate further includes a reinforcing rib 62 , which is arranged obliquely and has one end fixedly connected to the vertical sleeve 61 and the other end fixedly connected to the top surface of the transverse plate 6 .

[0040] In this embodiment, the displacement sensor 7 is a wire sensor, the bottom end of which is connected to the top end of the fixed rod. According to needs, the displacement sensor 7 can also be other sensors such as a magnetoresistive displacement meter, etc., but is not limited thereto.

[0041] The soft soil base generally includes a sand cushion layer, a soft soil layer, a hard soil layer and a bedrock layer from top to bottom. The calculated theoretical reference point depth is generally located above the bedrock layer, that is, there is no need to drill holes in advance, and the fixing rod can be driven into the depth of the theoretical reference point by a small hammering machine.

[0042] The method of using the reference point fixture is as follows:

[0043] First calculate the depth of the theoretical reference point;

[0044] Next, it is determined whether grouting is required to fix the drill bit 1. b ≤f s For example, it is necessary to perform grouting operation on the soil near the drill bit 1 to fix the drill bit 1;

[0045] Next, first connect the fixing rod, screw the drill bit 1 and a connecting rod 2 together, and use a small hammer machine to drive the fixing rod into the soil at the surface of the soft foundation treatment site. When the top of the connecting rod 2 is against the ground surface, extend another connecting rod 2 and continue to drive it downward until the drill bit 1 is at the depth of the theoretical reference point.

[0046] Then, the soil around the drill bit is poured through the grouting conduit 5 and the grouting hole 3, so that the entire fixing rod is fixed;

[0047] Finally, the settlement plate, displacement sensor 7 and collection device 8 are installed. When the ground settles, the settlement plate will sink with it. The pull-wire sensor obtains the settlement amount of the settlement plate and transmits the signal to the collection device 8, and the collection device 8 transmits the signal to the server.

[0048] The above description is only a preferred embodiment of the present invention, and therefore cannot be used to limit the scope of the present invention. That is, equivalent changes and modifications made according to the patent scope of the present invention and the contents of the specification should still fall within the scope of the present invention.

Claims

1. A reference point fixing device for settlement monitoring, characterized in that: It includes a settlement plate, a fixing rod, a displacement sensor and a collection device. The fixing rod includes a drill bit, a plurality of hollow connecting rods and a grouting conduit. The plurality of connecting rods are detachably connected end to end. The drill bit is fixedly connected to the bottom end of the connecting rod at the lowest end. The connecting rod at the lowest end is provided with a grouting hole close to the drill bit. The grouting conduit passes through each connecting rod in turn and is connected to the grouting hole. The settlement plate is placed on the foundation surface and can move up and down along the connecting rod. The displacement sensor can measure the descending depth of the settlement plate and is connected to the collection device. Drive the fixed rod into the soil until the drill bit moves to the theoretical reference point, and compare the negative friction f generated by the soil settlement above the reference point on the connecting rod. s and the end resistance f of the drill bit b If the size between b ≥f s , there is no need to grout the drill bit; if f b ≤f s , grouting operation is performed on the soil near the drill bit through the grouting pipe and the grouting hole to fix the drill bit; Where: Using the empirical coefficient a i Calculate f s ,Right now Where πd is the circumference of the connecting rod, h i is the thickness of each soil layer; according to f b =qπr 2 Calculate f b , where q is the empirical parameter of the end resistance, πr 2 is the drill bit plane area; The displacement sensor is a wire sensor, the bottom end of which is connected to the top end of the fixed rod; The grouting holes are provided in plurality and are arranged at intervals up and down.

2. The reference point fixing device for settlement monitoring according to claim 1 is characterized in that: The top end and the bottom end of the connecting rod are respectively provided with a first fixing portion and a second fixing portion, and two adjacent connecting rods are fixedly connected by the fixed cooperation of the first fixing portion and the second fixing portion.

3. The reference point fixing device for settlement monitoring according to claim 2 is characterized in that: The top end of the drill bit is provided with a third fixing part which can be matched with the second fixing part, and the connecting rod is fixedly connected to the drill bit through the fixed match between the second fixing part and the third fixing part.

4. The reference point fixing device for settlement monitoring according to claim 3 is characterized in that: The first fixing portion and the third fixing portion are both internal threads, and the second fixing portion is an external thread; or, the first fixing portion and the third fixing portion are both external threads, and the second fixing portion is an internal thread.

5. The reference point fixing device for settlement monitoring according to claim 1 is characterized in that: The settlement plate includes a transverse plate and a vertical sleeve fixed to the center of the transverse plate. The top end of the fixing rod passes through the transverse plate and extends into the vertical sleeve. The displacement sensor and the acquisition device are both installed at the top end of the vertical sleeve.

6. The reference point fixing device for settlement monitoring according to claim 5 is characterized in that: The settlement plate also includes a reinforcing rib, which is arranged obliquely and has one end fixedly connected to the vertical sleeve and the other end fixedly connected to the top surface of the transverse plate.

7. The reference point fixing device for settlement monitoring according to claim 1 is characterized in that: The connecting rod is made of rigid material.

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