Novel shield tunneling model device

Abstract

The utility model relates to a novel shield tunneling model device which comprises a model box body, a model shield tunneling machine and a pile body, the pile body is arranged between the model box body and the model shield tunneling machine, an I-shaped beam is arranged on the inner side wall of a box body opening of the model box body, and an arc-shaped rubber pad is arranged between the I-shaped beam and the pile body. And the arc surface of one side of the arc-shaped rubber pad is tightly attached to the arc surface of the pile body, and the other side of the arc-shaped rubber pad abuts against the I-shaped beam. According to the novel shield tunneling model device, the arc-shaped rubber pad is ingeniously used for simulating the soil resistance of a stratum, an experiment that a pile body does not penetrate into soil is achieved, evaluation can be conducted by directly observing the pile breaking condition of a pile foundation, and the arc-shaped rubber pad provides uniform supporting for the back of the pile body which does not penetrate into soil and simulates the soil resistance effect. The condition that the pile body is supported by stratum resistance is truly restored, the advantages of the pile body in-soil experiment and the pile body out-of-soil experiment are combined, the model device structure and the experiment steps are simplified, efficiency is higher, and application and popularization are facilitated.

Description

TECHNICAL FIELD

[0001] The utility model relates to a shield model device field, specifically speaking, a novel shield tunneling model device. BACKGROUND

[0002] When a shield method is used to build a new subway tunnel, the shield tunnel will inevitably pass through existing buildings and structures, and the probability of passing through will become higher and higher. Due to the characteristics of subway and underground engineering construction and the influence of many uncertain factors such as hydrogeology, there are many engineering construction risks in subway and underground engineering construction. In the past engineering, the shield machine cuts reinforced concrete piles in the soil layer. Due to incomplete cutting, winding and breaking of the reinforcement, the torque of the shield cutterhead instantaneously increases, causing damage to the cutterhead of the shield machine. Meanwhile, inappropriate shield tunneling parameters can easily cause large disturbance to the stratum during shield cutting of pile foundations, resulting in large settlement of the ground surface. Currently, in China, the optimization of shield tunneling parameters for cutting underground pile foundations only relies on analysis of the tunneling parameters provided by the engineering site, and the analysis results have large deviations.

[0003] The industry has introduced a shield simulation experiment method, in which strain gauges and other monitoring devices are attached to a model pile body, and a model shield machine with a reduced scale is used to cut the pile body. The strain force change during the destruction of the pile body is recorded to study the destruction mechanism of the pile body. The shield model experiment is divided into two cases: pile body entering the soil and pile body not entering the soil. The pile body cannot be effectively observed during the destruction process of being cut by the cutterhead after entering the soil. The shield machine cutting a single pile experiment without entering the soil can effectively avoid the above-mentioned shortcomings. However, because the pile body does not enter the soil, it lacks backward and lateral soil support, and the shield cannot truly restore the case of the pile body being supported by the stratum resistance when cutting the single pile without entering the soil. At the same time, the single pile experiment without entering the soil generally uses point support, and the back side of the pile foundation does not provide uniform support, so the pile body is prone to stress concentration under the action of the shield jacking force, causing the single pile to be sheared and a large number of transverse cracks to be generated, which interferes with the observation and analysis of the experimental results.

[0004] Therefore, the test system for determining shield tunneling parameters for cutting underground pile foundations disclosed in Chinese Patent Publication No. CN118407766A first performs a shield machine cutting single pile experiment without entering the soil, and then performs an overburden shield cutting pile foundation test. Although this technical solution can consider both experiments, two simulation devices need to be used, or the device needs to be adjusted after the first experiment to perform the second experiment. It can be seen that the existing model device requires a large number of quantities or has a complex structure, resulting in complicated and inconvenient experimental operation. UTILITY MODEL CONTENTS

[0005] In order to solve the problem that a single model device cannot simultaneously consider the experimental requirements of pile body into the soil and not into the soil in the prior art, resulting in that the simulation experiment needs to be carried out in stages and is relatively complicated, the utility model provides a novel shield tunneling model device.

[0006] The utility model discloses a technical scheme as follows:

[0007] A novel shield tunneling model device, including model box, model shield machine, pile body, the pile body sets up between the model box and the model shield machine, its characterized in that, the inner side wall of the box opening of model box is equipped with I -beam, the I -beam with the pile body between is equipped with arc rubber pad, and one side arc surface of the arc rubber pad is close to the pile body's pile body arc surface, and the other side of the arc rubber pad is against I -beam.

[0008] According to the utility model of the above scheme, its characterized in that, the cross section of arc rubber pad is fan ring shape, and the thickness of arc rubber pad is uniform.

[0009] According to the utility model of the above scheme, its characterized in that, the I -beam is parallel to the pile body, and can be detachably installed in the inside of box.

[0010] According to the utility model of the above scheme, its characterized in that, the pile body side is equipped with a plurality of laser displacement sensors, and the laser displacement sensor is used for detecting the inclination of the pile body after cutting.

[0011] According to the utility model of the above scheme, its characterized in that, the back side and the left and right sides of the pile body are arranged with a plurality of strain gauges along the axis direction of the pile body.

[0012] According to the utility model of the above scheme, its characterized in that, the outer side wall above the box opening is equipped with pile top fixed mounting piece, the pile top fixed mounting piece includes first arc slot block and second arc slot block, the first arc slot block is fixedly connected with the box, and the second arc slot block is detachably connected with the first arc slot block, the first arc slot block and the second arc slot block are buckled to form a clamping opening between them, and the clamping opening is used for clamping the top of the pile body.

[0013] Further, the first arc slot block and the second arc slot block are both provided with arc grooves, and screw holes are arranged on the sides of the arc grooves.

[0014] According to the utility model of the above scheme, the outer side wall below the box opening is provided with a pile base part support, and the bottom of the pile body is fixed on the pile base part support.

[0015] Further, the pile base part support is provided with a limiting slot, and the bottom of the pile body is arranged in the limiting slot.

[0016] According to the utility model, the model box body is provided with a shield propulsion support reaction frame on one side, the shield propulsion support reaction frame and the model box body enclose an installation space, the installation space is provided with a shield propulsion sliding support, the shield propulsion sliding support is provided with a curved sliding groove matched with the bottom of the model shield machine, the model shield machine is placed on the curved sliding groove, and the model shield machine is driven by a power equipment to excavate towards the box body.

[0017] According to the utility model, the model shield machine is placed on the curved sliding groove, and the model shield machine is driven by a power equipment to excavate towards the box body.

[0018] The novel shield excavation model device is characterized in that the arc-shaped rubber pad is used to simulate the soil resistance of the stratum, the pile body is not inserted into the soil, the pile foundation breaking condition can be directly observed and evaluated, the arc-shaped rubber pad provides uniform support for the back of the pile body not inserted into the soil, the soil resistance effect is simulated, the stratum resistance supporting condition of the pile body is truly restored, the advantages of the pile body inserted into the soil experiment and the pile body not inserted into the soil experiment are combined, the model device structure and the experimental steps are simplified, the efficiency is higher, and the novel shield excavation model device is beneficial to promotion and application. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 It is a structural schematic view of the utility model;

[0020] Figure 2 It is a partial enlarged view of the utility model;

[0021] Figure 3 It is a structural schematic view of the model shield machine, the pile body and the arc-shaped rubber pad in the utility model;

[0022] Figure 4 It is a force model schematic view of the rubber pad and the pile body.

[0023] In the drawings,

[0024] 1, model box body; 2, model shield machine; 3, pile body; 31, strain gauge; 4, arc-shaped rubber pad; 5, I-beam; 6, pile top fixed mounting piece; 7, pile base support; 8, shield propulsion support reaction frame; 81, side channel steel; 82, front steel plate; 9, shield propulsion sliding support. DETAILED DESCRIPTION

[0025] In order to better understand the purpose, technical scheme and technical effect of the utility model, the utility model is further explained in combination with the drawings and examples. It should be noted that similar signs and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further defined and explained in the subsequent drawings. At the same time, it is declared that the following described examples are only used to explain the utility model, and are not used to limit the utility model.

[0026] It should be noted that when an element is referred to as being "fixed" or "disposed" on another element, it can be directly on the other element or there can be an intervening element, and when an element is referred to as being "connected" to another element, it can be directly connected to the other element or there can be an intervening element.

[0027] The indicated spatial or positional relationship is based on the spatial or positional relationship shown in the drawings, or the spatial or positional relationship commonly used when the product of the application is used, or the spatial or positional relationship commonly understood by those skilled in the art, or the spatial or positional relationship commonly used when the product of the application is used, which is only for the purpose of facilitating the description of the application and simplifying the description, and therefore cannot be understood as limiting the application.

[0028] The terms "first", "second" are only for the purpose of facilitating the description, and cannot be understood as indicating or implying relative importance or implying the number of technical features. The meaning of "several" is two or more, unless otherwise specifically limited.

[0029] As shown in Figures 1 to 4 A new type of shield tunneling model device, comprising a model box 1, a model shield machine 2, a model pile body (hereinafter referred to as a pile body 3), and the pile body 3 is arranged between the model box 1 and the model shield machine 2. The box of the model box 1 is provided with an opening near the side of the model shield machine 2, the outer side wall of the box opening is detachably installed with the pile body 3, the inner side wall of the box opening is provided with an I-beam 5, and the I-beam 5 and the pile body 3 are provided with an arc-shaped rubber pad 4, and one side of the arc-shaped rubber pad 4 is tightly attached to the pile body arc surface of the pile body 3, and the other side of the arc-shaped rubber pad 4 is abutted against the I-beam 5. The I-beam 5 is used to provide rigid boundary support when the shield cuts the pile body 3.

[0030] Different sizes of arc-shaped rubber pads have different stiffness, which can simulate the action of stratum resistance, so the size of the arc-shaped rubber pad 4 is cut according to the horizontal base coefficient of the simulated stratum. The cutting size of the arc-shaped rubber pad 4 can be calculated by an equivalent rectangular rubber pad, because the arc-shaped rubber pad tightly fits the pile body curved surface, and the shield thrust of the pile body is applied to the arc-shaped rubber pad, which is equivalent to the vertical load applied to the rectangular rubber pad plane.

[0031] The stiffness calculation formula of the rectangular rubber pad under the action of vertical load is as follows:

[0032] G=0.117e 0.03HS (1)

[0033] E a =iG (2)

[0034] i = 3.6 (1 + 2.22S 2 ) (3)

[0035]

[0036] In the formula, G is the shear modulus of the rubber material, in MPa; HS is the Shore hardness of the rubber; E is the apparent modulus of the compressed rubber spring; i is the geometric shape factor; S is the ratio of the bearing area to the free area of the rectangular rubber spring, the bearing area being the area of the side on which the contact load is applied, and the free area being the area remaining after the bearing area is removed; a and b are the length and width of the rectangular rubber pad, respectively, in mm; h is the thickness of the rectangular rubber pad, in mm; P is the rubber stiffness, in N / mm; and K is the equivalent subgrade modulus of the rubber pad, in GPa / m. a

[0037] It can be seen that the equivalent subgrade modulus of the rubber pad can be changed by adjusting the Shore hardness and size of the rubber pad, so as to simulate the horizontal subgrade modulus of different types of strata. The principle is that the pile axis is perpendicular to the ground, and when the shield is pushed to cut the pile, the resistance direction of the stratum is perpendicular to the shield cutter, which can be regarded as the horizontal direction, so the simulation of the stratum resistance mainly considers the simulation of the horizontal stratum resistance; and the stratum resistance calculation formula is: stratum resistance = horizontal subgrade modulus x displacement; therefore, the equivalent of the horizontal subgrade modulus is focused on when simulating the stratum resistance.

[0038] Through data query, it is known that the stratum types include mucky clay, medium-coarse sand, silty clay, sandy clay, fully weathered granite, and strongly weathered granite, the horizontal subgrade modulus of the mucky clay is 20.97 MPa / m, the horizontal subgrade modulus of the medium-coarse sand is 21.80 MPa / m, the horizontal subgrade modulus of the silty clay is 53.63 MPa / m, the horizontal subgrade modulus of the sandy clay is 62.91 MPa / m, and the horizontal subgrade modulus of the fully weathered granite is 35-40 MPa / m. For details, refer to the following table:

[0039]

[0040] ​After determining the simulated stratum type, the horizontal base bed coefficient Kh of the stratum is known, the equivalent stratum base bed coefficient K of the rubber pad is equal to the horizontal base bed coefficient Kh of the stratum, the Shore hardness and size of the rectangular rubber pad are calculated and deduced according to the formula, and the length, width and thickness of the rectangular rubber pad are obtained. For example, the simulated stratum type is determined as fully weathered granite, the horizontal base bed coefficient Kh of the stratum is known as 35-40 (Mpa / m), the equivalent stratum base bed coefficient K of the rectangular rubber pad is 35-40 (Mpa / m), and the size of the rectangular rubber pad can be deduced by using the above formula (1)-(6). Specifically, the length, width and thickness of the rectangular rubber pad can be deduced by the equivalent stratum base bed coefficient = stiffness ÷ (length x width), and the stiffness = apparent elastic modulus of the rectangular rubber pad x (length x width) ÷ thickness.

[0041] The arc length of the arc-shaped rubber pad 4 is equal to the length of the rectangular rubber pad, the arc length in the width direction of the arc-shaped rubber pad 4 is equal to the width of the rectangular rubber pad, and the thickness of the arc-shaped rubber pad 4 is equal to the thickness of the rectangular rubber pad, so that the cutting size of the arc-shaped rubber pad 4 is obtained.

[0042] In the utility model, the cross section of the arc-shaped rubber pad 4 is fan ring shape, the thickness of the arc-shaped rubber pad 4 is uniform, and the soil body uniformly wraps the back of the pile body 3.

[0043] In the utility model, the physical and mechanical parameters of the model pile body are calculated and determined by similarity simulation, and the calculation is as follows:

[0044] Pile diameter of the pile body: Wherein R m is the pile diameter of the model pile body; R p is the pile diameter of the prototype pile foundation; C L is the geometric similarity ratio of the model experiment.

[0045] Elastic modulus: Wherein E m is the elastic modulus of the model pile body; E p is the elastic modulus of the prototype pile foundation.

[0046] Compressive strength of the pile body: Wherein σ m is the compressive strength of the model pile body; σ p is the compressive strength of the prototype pile foundation.

[0047] Steel bar tension and compression stiffness: Wherein E m is the elastic modulus of the model steel bar; A m is the sectional area of the model steel bar; E p is the elastic modulus of the prototype steel bar; A p is the sectional area of the prototype steel bar.

[0048] The model box 1 is filled with heavy objects, so that the box is not easy to be moved, and can provide back support for the arc-shaped rubber pad and the pile body.

[0049] In the utility model, a plurality of laser displacement sensors are arranged at a certain distance from the pile body 3 on the side of the box, so as to measure the inclination of the pile body 3 from different angles by means of the laser displacement sensors. The distance between the laser displacement sensors and the pile body 3 is ensured to be able to detect the pile body 3 by the sensing distance of the laser displacement sensors. A plurality of strain gauges 31 are arranged on the back side and the left and right sides of the pile body 3 along the axis direction of the pile body 3, and the strain gauges 31 are used to test the internal force change data of the pile body 3 in the cutting process, including the bending moment change data.

[0050] In the utility model, the outer side wall above the opening of the box is provided with a pile top fixed mounting piece 6, the pile top fixed mounting piece 6 includes a first arc-shaped groove block and a second arc-shaped groove block, the first arc-shaped groove block is fixedly connected with the box, the second arc-shaped groove block is detachably connected with the first arc-shaped groove block, and the first arc-shaped groove block and the second arc-shaped groove block are both provided with arc-shaped grooves, and screw holes are arranged on the sides of the arc-shaped grooves. The size and shape of the second arc-shaped groove block and the first arc-shaped groove block are matched, and the two are mutually buckled to have a circular or elliptical clamping opening in the middle, and the second arc-shaped groove block and the first arc-shaped groove block can clamp the top of the pile body 3 through the clamping opening. In use, first, the top of the pile body 3 is placed in the arc-shaped groove of the first arc-shaped groove block, then the arc-shaped groove of the second arc-shaped block is buckled on the other side of the pile body 3, and finally, the bolts are passed through the corresponding screw holes of the two arc-shaped groove blocks and are tightened to complete the installation of the top of the pile body 3.

[0051] In the utility model, the outer side wall below the opening of the box is provided with a pile base part support 7, the pile base part support 7 is placed on the ground or the same platform together with the box, and the pile base part support 7 is fixedly connected with the box, and the bottom of the pile body 3 is fixed on the pile base part support 7. In order to prevent the pile body 3 from being displaced in the cutting process, a limiting slot can be arranged on the pile base part support 7, and the bottom of the pile body 3 is arranged in the limiting slot, which can better fix the bottom end of the pile body 3.

[0052] In the utility model, the I-beam 5 is arranged in the box in parallel to the pile body 3, which can increase the abutting surface with the arc-shaped rubber pad 4 and ensure that the arc-shaped rubber pad 4 is tightly attached to the pile body curve surface of the pile body 3. The I-beam 5 is fixed to the inner side wall of the box in a detachable manner. When the thickness of the required arc-shaped rubber pad 4 is large and the space between the I-beam 5 and the pile body 3 is insufficient to place the arc-shaped rubber pad 4, the I-beam 5 can be detached, and the I-beam 5 is slightly adjusted and moved to the inside of the box and is reinstalled and fixed. In an optional embodiment, if the size of the arc-shaped rubber pad 4 is too small, a gap will be generated between the I-beam 5 and the arc-shaped rubber pad 4, and the I-beam 5 and the arc-shaped rubber pad 4 are provided with steel plates (not shown in the figure), which can make up for the gap.

[0053] In the utility model, the model box 1 side is equipped with shield propulsion support reaction frame 8, shield propulsion support reaction frame 8 includes side channel steel 81 and front steel plate 82, and the both sides of the box are provided with three parallel side channel steels 81, and each side channel steel 81 is reversely bent and welded with the edge of the box, and the front steel plate 82 is connected with the side channel steel 81 of the both sides of the box, and specifically, the side of the front steel plate 82 extends and is provided with a connecting channel steel, and the connecting channel steel is welded with the side channel steel 81 of the corresponding height. The center of the front steel plate 82 is provided with a square hole to ensure that the oil pump of the model shield machine 2 can pass through, and the oil pump is prevented from abutting against the front steel plate 82.

[0054] The shield propulsion support reaction frame 8 and the model soil box enclose an installation space, and the model shield machine 2 is placed in the installation space, and specifically, the installation space is provided with a shield propulsion sliding support 9, and the shield propulsion sliding support 9 is provided with a curved sliding groove matched with the bottom of the model shield machine 2, and the model shield machine 2 is driven by a power device to excavate in the direction of the box on the shield propulsion sliding support 9.

[0055] In use, the model shield machine 2 is first set with initial excavation parameters, and the excavation parameters include shield thrust and cutter head rotating speed, and the setting steps include:

[0056] The initial cutter head rotating speed of the model shield machine 2 is determined by a different stratum cutter head rotating speed table, and the initial shield thrust of the model shield machine 2 is calculated according to a formula, and the formula is:

[0057] In the formula, n is the number of cutting hobs, b is the width of the hob blade, v is the shield excavation speed, σ t is the pile foundation compressive strength, p is the shield cutter head rotating speed, and k is the geometric similarity ratio of the model experiment.

[0058] The different stratum cutter head rotating speed table is as follows:

[0059] stratum maximum minimum soft stratum 1.2 0.7 soft over hard stratum 2.0 0.9 hard rock stratum 2.3 1.7

[0060] The maximum value and the minimum value of the shield cutter head rotating speed are determined according to the above table, then any value in the interval range of the maximum value and the minimum value is selected as one of the initial excavation parameters, the conventional shield excavation speed is taken as one of the initial excavation parameters, and the shield thrust is calculated by substituting the shield thrust formula.

[0061] The model shield machine 2 is started to cut the pile body 3, and the pile foundation breaking condition is observed during the cutting process, and the evaluation standard of the pile foundation breaking condition includes:

[0062] A. The model shield machine 2 can cut the pile body;

[0063] B. The cut pile body does not produce transverse cracks and does not present block crushing;

[0064] C. The bending moment and strain of the pile body meet the requirements.

[0065] In the embodiment, the requirement criteria of the bending moment and strain of the pile body include that the inclination angle of the pile body 3 after cutting is less than 2°, and the maximum bending moment is less than 300 N·m.

[0066] The tunneling parameters are adjusted according to the evaluation results until the evaluation criteria are met, and the optimal tunneling parameters are determined.

[0067] In summary, the utility model provides a novel shield tunneling model device, which ingeniously uses the arc-shaped rubber pad to simulate the soil resistance of the stratum, realizes the experiment of the pile body not entering the soil, can evaluate by directly observing the pile breaking of the pile foundation, and the arc-shaped rubber pad provides uniform support for the back of the pile body not entering the soil, simulates the soil resistance effect, truly restores the condition of the pile body being supported by the stratum resistance, combines the advantages of the pile body entering the soil and not entering the soil, simplifies the structure of the model device and the experimental steps, is more efficient, and is beneficial to popularization and application.

[0068] The technical features of the above embodiments can be combined arbitrarily, and to make the description concise, all possible combinations of the technical features in the above embodiments are not described, however, as long as the combination of the technical features does not exist contradictory, it should be considered that it is within the scope of the present application.

[0069] The above embodiments only express several implementation manners of the utility model, the description is more specific and detailed, but it should not be understood as the limitation of the scope of the utility model patent. It should be pointed out that for ordinary skilled in the art, without departing from the concept of the utility model, a number of modifications and improvements can be made, which belong to the protection scope of the utility model. Therefore, the protection scope of the utility model patent should be subject to the appended claims.

Claims

1. A novel shield tunneling model device, comprising a model box, a model shield machine, a pile body, the pile body being arranged between the model box and the model shield machine, characterized in that, The inner side wall of the box opening of the model box is provided with an I-beam, an arc-shaped rubber pad is arranged between the I-beam and the pile body, and one side of the arc-shaped rubber pad is tightly attached to the pile body arc surface, and the other side of the arc-shaped rubber pad is tightly attached to the I-beam.

2. The new shield tunneling model device according to claim 1, wherein, The cross section of the arc-shaped rubber pad is in the shape of a fan ring, and the thickness of the arc-shaped rubber pad is uniform.

3. The new shield tunneling model device according to claim 1, wherein, The I-beam is parallel to the pile body and can be detachably installed inside the box.

4. The new shield tunneling model device according to claim 1, wherein, A plurality of laser displacement sensors are arranged beside the pile body, and the laser displacement sensors are used to detect the inclination of the pile body after cutting.

5. The new shield tunneling model device according to claim 1, wherein, A plurality of strain gauges are arranged on the back side and the left and right sides of the pile body along the pile body axis direction.

6. The new model device of shield tunneling according to claim 1, wherein, The outer side wall above the box opening is provided with a pile top fixed mounting member, the pile top fixed mounting member includes a first arc-shaped groove block and a second arc-shaped groove block, the first arc-shaped groove block is fixedly connected with the box, and the second arc-shaped groove block is detachably connected with the first arc-shaped groove block; after the first arc-shaped groove block and the second arc-shaped groove block are buckled, a clamping opening is formed between the two, and the clamping opening is used to clamp the top of the pile body.

7. The new model device of tunneling shield according to claim 6, characterized in that, The first arc-shaped groove block and the second arc-shaped groove block are both provided with an arc-shaped groove, and a screw hole is arranged beside the arc-shaped groove.

8. The new type of shield tunneling model device according to claim 1 or 6, characterized in that, The outer side wall below the box opening is provided with a pile base support, and the bottom of the pile body is fixed on the pile base support.

9. The new shield tunneling model device according to claim 8, wherein, The pile base support is provided with a limiting slot, and the bottom of the pile body is arranged in the limiting slot.

10. The new model device of tunneling shield according to claim 1, characterized in that, One side of the model box is provided with a shield propulsion support reaction frame, the shield propulsion support reaction frame and the model box enclose an installation space, the installation space is provided with a shield propulsion sliding support, the shield propulsion sliding support is provided with a curved sliding groove matched with the bottom of the model shield machine, the model shield machine is arranged on the curved sliding groove, and the model shield machine is driven by a power equipment to excavate towards the box.

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