阅读说明：本技术 一种用于基坑模型试验的竖向围护结构水平位移监测装置 (A vertical envelope horizontal displacement monitoring devices for foundation ditch model test ) 是由 徐晓兵 叶泽锋 李俊逸 胡敏云 张腾遥 于 2021-07-02 设计创作，主要内容包括：一种用于基坑模型试验的竖向围护结构水平位移监测装置,包括模型箱、基坑模型试验系统和监测系统；所述模型箱由模型箱框架、侧板和底板组成,模型箱内填装有试验土体；所述基坑模型试验系统设置在模型箱的中部,由竖向围护结构和内支撑组成；所述监测系统包括细钢丝、定滑轮和数显百分表,细钢丝一端固定在竖向围护结构的预设孔洞上,另一端水平延伸至定滑轮,绕经定滑轮后竖直向上与数显百分表连接。本发明可在模型试验中监测竖向围护结构的水平位移；可模拟在不同工况下,监测任意不同深度处的竖向围护结构水平位移,为基坑的变形分析提供有效的试验数据支持,对基坑受力与变形的发展规律提供依据。(A vertical enclosure structure horizontal displacement monitoring device for a foundation pit model test comprises a model box, a foundation pit model test system and a monitoring system; the model box consists of a model box frame, side plates and a bottom plate, and a test soil body is filled in the model box; the foundation pit model test system is arranged in the middle of the model box and consists of a vertical enclosure structure and an inner support; the monitoring system comprises a thin steel wire, a fixed pulley and a digital display dial indicator, wherein one end of the thin steel wire is fixed on a preset hole of the vertical enclosure structure, the other end of the thin steel wire horizontally extends to the fixed pulley, and the thin steel wire is vertically upwards connected with the digital display dial indicator after being wound around the fixed pulley. The invention can monitor the horizontal displacement of the vertical enclosure structure in the model test; the horizontal displacement of the vertical enclosure structure at any different depths can be monitored under different working conditions, effective test data support is provided for deformation analysis of the foundation pit, and basis is provided for the development rule of stress and deformation of the foundation pit.)

1. The utility model provides a vertical envelope horizontal displacement monitoring devices for foundation ditch model test which characterized in that: the device comprises a model box (1), a foundation pit model test system (2) and a monitoring system (3);

the model box (1) is placed on a hardened flat ground, the model box (1) comprises a model box frame, side plates (1-1) and a bottom plate (1-2), the model box frame is a cubic frame, the side plates (1-1) are fixed on the side walls of the cubic frame, and the bottom plate (1-2) is fixed on the bottom surface of the cubic frame; a test soil body is filled in the model box (1), and a foundation pit is excavated in the test soil body;

the foundation pit model test system (2) comprises vertical enclosing structures (2-1) arranged around a foundation pit and inner supports (2-2) arranged between the vertical enclosing structures (2-1), holes are formed in the same vertical section of the vertical enclosing structures (2-1) at equal intervals along the vertical direction, the positions of the holes are monitoring points, and the sizes of the holes are matched with first bolts (3-2a) arranged on the monitoring system (3);

the monitoring system (3) comprises a thin steel wire (3-1), an internal thread hollow aluminum pipe (3-3), a fixed pulley (3-4), a pulley protection box (3-5), a digital display dial indicator (3-6), a magnetic suction seat (3-7), a sliding block (3-8), a locking limit wrench (3-9), a guide rail (3-10), a steel pipe cross beam (3-11) and a support (3-12); one end of the thin steel wire (3-1) is fixed on the vertical enclosing structure (2-1) of the preset hole through a first bolt (3-2 a); an internal thread hollow aluminum pipe (3-3) is sleeved outside the thin steel wire (3-1), and the internal thread hollow aluminum pipe (3-3) isolates a test soil body from the thin steel wire (3-1); the other end of the thin steel wire (3-1) horizontally extends to the fixed pulley (3-4), and is wound around the fixed pulley (3-4) and then vertically and upwards connected to a digital display dial indicator (3-6) above a test soil body; the digital display dial indicator (3-6) is fixed on the steel pipe cross beam (3-11) through the magnetic suction seat (3-7), and the steel pipe cross beam (3-11) is horizontally erected above the model box (1) through the support (3-12); the total length of the thin steel wire (3-1) is unchanged, and the horizontal displacement of the vertical enclosure structure is reflected through the change of the reading of the digital display dial indicator (3-6); the fixed pulleys (3-4) are arranged in pulley protection boxes (3-5), the pulley protection boxes (3-5) are arranged on sliding blocks (3-8) with clamping holes through buckles, locking limit wrenches (3-9) are attached to the sliding blocks (3-8), and the sliding blocks (3-8) can freely move or be fixed on the guide rails (3-10) in a screwing mode so as to monitor the horizontal displacement of the vertical enclosure structure at different depths; the sliding blocks (3-8) are arranged in the guide rails (3-10) in a sliding mode, and the guide rails (3-10) are vertically fixed on the inner walls of the side plates (1-1) of the model box (1) through second bolts (3-2 b).

2. The vertical enclosure horizontal displacement monitoring device for the foundation pit model test as claimed in claim 1, wherein: the surface of the fine steel wire (3-1) is coated with vaseline to reduce contact friction.

3. The vertical enclosure horizontal displacement monitoring device for the foundation pit model test as claimed in claim 1, wherein: the vertical enclosure structure (2-1) comprises a diaphragm wall, an enclosure pile or a Larsen steel sheet pile.

4. The vertical enclosure horizontal displacement monitoring device for the foundation pit model test as claimed in claim 1, wherein: the pulley protection boxes (3-5) are divided into different pulley protection box (3-5) types according to the number of the test points, wherein avoidance holes for avoiding the thin steel wires (3-1) below are arranged on the pulley protection boxes (3-5) above the pulley protection boxes in a penetrating mode.

5. The vertical enclosure horizontal displacement monitoring device for the foundation pit model test as claimed in claim 1, wherein: internal threads are arranged at two ends of the internal thread hollow aluminum pipe (3-3), and the internal thread hollow aluminum pipe (3-3) is in threaded connection with the pulley protection box (3-5); the length of the internal thread hollow aluminum pipe (3-3) is matched with that of the thin steel wire (3-1).

6. The vertical enclosure horizontal displacement monitoring device for the foundation pit model test as claimed in claim 1, wherein: the sliding blocks (3-8) are internally provided with rollers, and the sliding blocks (3-8)) are in sliding connection with the guide rails (3-10) through the rollers; the sliding block (3-8) is provided with a locking limit wrench (3-9), the locking limit wrench (3-9) is provided with a brake pad, and the locking limit wrench (3-9) is turned to enable the brake pad to be locked with the guide rail (3-10) due to friction to generate braking action.

Technical Field

The invention relates to a foundation pit model test monitoring device, in particular to a vertical enclosure structure horizontal displacement monitoring device for a foundation pit model test.

Background

With the vigorous development and construction of urban underground spaces, foundation pits are continuously developed in the direction of deeper depth, larger scale and size and more compact foundation pit field. The foundation pit is gradually excavated, and the soil body in the foundation pit is gradually unloaded, so that the soil pressure difference is generated inside and outside the foundation pit, and the vertical enclosure structure is caused to generate horizontal displacement, so that the deformation and the stability of the foundation pit are further influenced, and the problems of the deformation and the instability of the foundation pit caused by the horizontal displacement of the vertical enclosure structure are one of major risk sources of the current foundation pit engineering.

Although the current specification has the specification of the calculation requirement of the horizontal displacement of the vertical enclosure structure, the principle of the design calculation is simple. At present, the commonly used numerical software calculation is a simplification of an engineering example model, and the required soil constitutive parameters are difficult to accurately measure, so that the influence on the result is great, and the reference is low. However, in the existing field measurement method, because the uncontrollable factors of the engineering field conditions are too many, the data of field monitoring can not be really obtained at all sometimes.

The foundation pit model test has strong controllability, and the obtained data can be used for calculating the deformation stress condition of the actual engineering foundation pit according to the scaling ratio. At present, there is no reliable method for monitoring the horizontal displacement of the vertical enclosure structure of the foundation pit in a model test, and accurate monitoring of the horizontal displacement of the vertical enclosure structure is one of the keys for carrying out correct test data analysis.

Therefore, the designed foundation pit supporting structure has strong operability, can monitor the horizontal displacement of the vertical enclosing structure at different depths under different excavation working conditions, and has great significance for accurately evaluating the working properties of the foundation pit supporting structure.

Disclosure of Invention

In order to overcome the problems, the invention provides a vertical enclosure structure horizontal displacement monitoring device for a foundation pit model test.

The technical scheme adopted by the invention is as follows: a vertical enclosure structure horizontal displacement monitoring device for a foundation pit model test comprises a model box, a foundation pit model test system and a monitoring system;

the model box is placed on a hardened flat ground and comprises a model box frame, side plates and a bottom plate, wherein the model box frame is a cubic frame, the side plates are fixed on the side walls of the cubic frame, and the bottom plate is fixed on the bottom surface of the cubic frame; a test soil body is filled in the model box, and a foundation pit is excavated in the test soil body;

the foundation pit model test system comprises vertical enclosing structures arranged around a foundation pit and inner supports arranged between the vertical enclosing structures, holes are formed in the same vertical section of each vertical enclosing structure at equal intervals along the vertical direction, the positions of the holes are monitoring points, and the sizes of the holes are matched with first bolts equipped by the monitoring system;

the monitoring system comprises a thin steel wire, an internal thread hollow aluminum pipe, a fixed pulley, a pulley protection box, a digital display dial indicator, a magnetic suction seat, a sliding block, a locking limit wrench, a guide rail, a steel pipe cross beam and a support; one end of the thin steel wire is fixed on the vertical enclosing structure of the preset hole through a first bolt; an internal thread hollow aluminum pipe is sleeved outside the thin steel wire and used for isolating the test soil body from the thin steel wire; the other end of the thin steel wire horizontally extends to the fixed pulley, and is vertically and upwardly connected to a digital display dial indicator above the test soil body after being wound around the fixed pulley; the digital display dial indicator is fixed on the steel pipe cross beam through the magnetic suction seat, and the steel pipe cross beam is horizontally erected above the model box through the bracket; the total length of the thin steel wire is unchanged, and the horizontal displacement of the vertical enclosure structure is reflected through the change of the reading of the digital display dial indicator; the fixed pulley is arranged in a pulley protection box, the pulley protection box is arranged on a sliding block which is fixed on a clamping hole through a buckle, a locking limit spanner is attached to the sliding block, and the sliding block can freely move or be fixed on the guide rail through a rotating and twisting mode so as to monitor the horizontal displacement of the vertical enclosure structure at different depths; the slide block is arranged in the guide rail in a sliding mode, and the guide rail is vertically fixed to the inner wall of the side plate of the model box through a second bolt.

Further, the surface of the fine steel wire is coated with vaseline to reduce contact friction.

Further, the vertical enclosure structure is in a type of a diaphragm wall, an enclosure pile or a Larsen steel sheet pile.

Further, the pulley protection boxes are divided into different pulley protection box types according to the number of the monitoring points, wherein the pulley protection boxes positioned above are provided with avoiding holes for avoiding the thin steel wires positioned below in a penetrating manner.

Furthermore, internal threads are arranged at two ends of the internal thread hollow aluminum pipe, and the internal thread hollow aluminum pipe is in threaded connection with the pulley protection box; the length of the internal thread hollow aluminum pipe is matched with the length of the thin steel wire.

Furthermore, a roller is arranged in the sliding block, and the sliding block is connected with the guide rail in a sliding manner through the roller; the sliding block is provided with a locking limit wrench, the locking limit wrench is provided with a braking piece, and the locking limit wrench is turned to enable the braking piece to be locked by friction when the braking piece is connected with the guide rail, so that braking action is generated.

The invention has the beneficial effects that:

(1) the invention can realize the monitoring of the horizontal displacement of the vertical space enclosing structure buried under the soil body in the model test.

(2) The invention monitors the horizontal displacement of the vertical enclosure structure by a direct measurement method, is different from the traditional method of attaching a strain gauge on the vertical enclosure structure and improving the accuracy by a method of inversely calculating the displacement by internal force.

(3) The invention designs a monitoring device for the horizontal displacement of the vertical enclosure structure in the foundation pit model test system, and simultaneously can realize the measurement of the horizontal displacement of the vertical enclosure structure at different depths through the tracks on the side wall.

(4) The invention has simple structure, low cost and strong operability.

Drawings

FIG. 1 is a side view of a model test apparatus of the present invention.

FIG. 2 is a horizontal displacement model test monitoring device for a vertical envelope structure.

Fig. 3 a-c are schematic diagrams of pulley protection box models with different specifications.

Figure 4a is a cross-sectional view of a linear track of the present invention.

Figure 4b is a side view of the linear track of the present invention.

Description of reference numerals: 1, a model box; 1-1 side plate; 1-2 bottom plates; 2, a foundation pit model test system; 2-1, vertical enclosing structures; 2-2, supporting; 3, monitoring the system; 3-1 thin steel wire; 3-2a first bolt; 3-2b second bolt; 3-3 of a hollow aluminum tube with internal threads; 3-4 fixed pulleys; 3-5 pulley protection boxes; 3-6 digital display dial indicators; 3-7 magnetic force suction base; 3-8 sliding blocks; 3-9 locking a limit wrench; 3-10 guide rails; 3-11 steel tube cross beams; 3-12 of bracket.

Detailed Description

The technical solutions of the present invention will be described clearly and completely with reference to the accompanying drawings, and it should be understood that the described embodiments are only some embodiments, but not all embodiments, of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In the description of the present invention, it should be noted that the orientations or positional relationships indicated as the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., appear based on the orientations or positional relationships shown in the drawings only for the convenience of describing the present invention and simplifying the description, but not for indicating or implying that the referred devices or elements must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and "third" as appearing herein are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

In the description of the present invention, it should be noted that, unless otherwise explicitly stated or limited, the terms "mounted," "connected," and "connected" should be interpreted broadly, e.g., as being fixed or detachable or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.

Referring to the attached drawings, the device comprises a model box 1, a foundation pit model testing system 2 and a monitoring system 3; the model box 1 consists of a model box frame, side plates 1-1 and a bottom plate 1-2, and test soil is filled in the model box; the model box frame is placed on a hardened flat ground, a bottom plate is fixed at the bottom of the model box frame, side plates are fixed on the peripheral sides of the model box frame, and the model box frame and the bottom plate are connected in a welding mode;

the foundation pit model test system 2 consists of a vertical enclosure structure 2-1 and an inner support 2-2; a plurality of bolt holes which are equally spaced along the vertical direction are formed in the same section of the vertical enclosure structure, and the size of each hole is matched with that of a bolt equipped by a monitoring system;

the monitoring system 3 consists of a thin steel wire 3-1, a bolt 3-2, an internal thread hollow aluminum pipe 3-3, a fixed pulley 3-4, a pulley protection box 3-5, a digital display dial indicator 3-6, a magnetic suction seat 3-7, a sliding block 3-8, a locking limit wrench 3-9, a guide rail 3-10, a steel pipe beam 3-11 and a support 3-12; vaseline is coated on the surface of the thin steel wire 3-1 and is fixed on a vertical enclosing structure with a preset hole through a first bolt 3-2a, and the size of the hole is matched with that of a bolt of a monitoring device; the thin steel wire 3-1 is externally sleeved with an internal thread hollow aluminum pipe 3-3 for isolating a soil body from the thin steel wire and playing a role in protecting the thin steel wire; the thin steel wire 3-1 is arranged at a horizontal corner, the stress direction of the thin steel wire 3-1 is changed by means of a fixed pulley 3-4, and the thin steel wire is finally connected to a digital display dial indicator 3-6 above the earth surface soil body; the digital display dial indicators 3-6 are fixed on the steel pipe cross beams 3-11 through magnetic suction seats 3-7; the steel pipe cross beams 3-11 are erected on the brackets 3-12; the internal thread hollow aluminum pipe 3-3 is connected with the pulley protection box 3-5 in a threaded connection mode; the pulley protection box 3-5 plays a role of protecting a fixed pulley at a corner and is fixed on a sliding block 3-8 with a clamping hole through a buckle; a locking limit wrench 3-9 is attached to the sliding block 3-8, and can freely move and be fixed on the guide rail 3-10 in a rotating and twisting mode so as to monitor the horizontal displacement of the vertical enclosure structure at different depths; the guide rail 3-10 is fixed on the side wall of the model box through a second bolt 3-2 b.

Referring to fig. 1, a mold box 1 in a side view of the mold testing apparatus is composed of four side plates 1-1 and a bottom plate 1-2; the side plates and the bottom plate are welded into a whole to form a cuboid model box with an open top surface, and the cuboid model box is used for filling excavation of rock and soil bodies and burying of the monitoring device.

Referring to the attached figure 2, the vertical enclosure structure horizontal displacement model test monitoring device comprises 3-1 parts of thin steel wires, 3-2a parts of first bolts, 3-2b parts of second bolts, 3-3 parts of internal thread hollow aluminum pipes, 3-4 parts of fixed pulleys, 3-5 parts of pulley protection boxes, 3-6 parts of digital display dial indicators, 3-7 parts of magnetic suction seats, 3-8 parts of sliding blocks, 3-9 parts of locking limit wrenches, 3-10 parts of guide rails, 3-11 parts of steel pipe cross beams and 3-12 parts of supports; vaseline is coated on the surface of the thin steel wire 3-1 and is fixed on a vertical enclosing structure with a preset hole through a first bolt 3-2a, and the size of the hole is matched with that of a bolt of a monitoring device; the thin steel wire 3-1 is externally sleeved with an internal thread hollow aluminum pipe 3-3 for isolating a soil body from the thin steel wire and playing a role in protecting the thin steel wire; the thin steel wire 3-1 is arranged at a horizontal corner, the stress direction of the thin steel wire 3-1 is changed by means of a fixed pulley 3-4, and the thin steel wire is finally connected to a digital display dial indicator 3-6 above the earth surface soil body; the digital display dial indicators 3-6 are fixed on the steel pipe cross beams 3-11 through magnetic suction seats 3-7; the steel pipe cross beams 3-11 are erected on the brackets 3-12; the internal thread hollow aluminum pipe 3-3 is connected with the pulley protection box 3-5 in a threaded connection mode; the pulley protection box 3-5 plays a role of protecting a fixed pulley at a corner and is fixed on a sliding block 3-8 with a clamping hole through a buckle; a locking limit wrench 3-9 is attached to the sliding block 3-8, and can freely move and be fixed on the guide rail 3-10 in a rotating and twisting mode so as to monitor the horizontal displacement of the vertical enclosure structure at different depths; the guide rail 3-10 is fixed on the side wall of the model box through a second bolt 3-2 b.

Referring to the attached figure 3, a model schematic diagram of pulley protection boxes with three different specifications is shown, the type of the required specification is determined according to the number of monitoring points to be monitored, the pulley protection box 3-5 corresponding to the monitoring point with the deepest depth has the smallest specification, the specification is larger upwards, the pulley protection box is provided with an externally threaded connecting pipe, and the right side of the pulley protection box is provided with a buckle 3-13 to play a role in fixing; the pulley protection box 3-5 is internally provided with a fixed pulley 3-4, and the fixed pulley 3-4 is used for changing the stress direction of the thin steel wire 3-1.

Referring to fig. 4a and 4b, the linear track is composed of guide rails 3-10 and sliding blocks 3-8; the guide rails 3-10 are connected with the side plates of the model box through bolts; a roller is arranged in the sliding block 3-8, and the sliding block is connected with the guide rail 3-10 in a sliding manner through the roller; the sliding blocks 3-8 are provided with locking limit wrenches, the locking limit wrenches are provided with brake pads, the locking limit wrenches are turned to enable the brake pads to generate braking action due to friction locking when the brake pads are connected with the guide rail, free sliding and fixing can be achieved, and the number of the sliding blocks is determined according to the number of the monitoring points.

The method is suitable for monitoring the horizontal displacement of the vertical enclosure structure while excavating the soil body in the foundation pit in the model test process, and can dynamically monitor the horizontal displacement of the vertical enclosure structure at different depths according to actual requirements.

The embodiments described in this specification are merely illustrative of implementations of the inventive concept and the scope of the present invention should not be considered limited to the specific forms set forth in the embodiments but rather by the equivalents thereof as may occur to those skilled in the art upon consideration of the present inventive concept.