External pressure test device and method based on simulated loading of side soil pressure of concrete box culvert

Abstract

The invention discloses an external pressure test device and method based on simulated loading of side soil pressure of a concrete box culvert, the external pressure test device comprises a base, a vertical loading assembly, a lateral loading assembly and a first pressure sensor, and the base is provided with a test station; the vertical loading assembly comprises a vertical loading piece; the lateral loading assembly comprises a first counter-force beam, a second counter-force beam and an elastic piece, the first counter-force beam and the second counter-force beam are arranged on the two sides of the concrete box culvert in the first direction respectively, the elastic piece is arranged on the side, facing the concrete box culvert, of the first counter-force beam, the position of the first counter-force beam in the first direction is adjustable, and the second counter-force beam abuts against the concrete box culvert; the first pressure sensor is arranged on the vertical loading piece; thus, the vertical loading piece is used for simulating the long-term traffic load of the earth surface, the lateral loading assembly is used for applying the load to simulate the soil pressure, the actual engineering condition can be closer, the accuracy of the test result is improved, and therefore it is guaranteed that the concrete box culvert has higher safety in actual engineering use.

Description

Technical Field

[0001] The invention relates to the technical field of external pressure testing of concrete box culverts, and in particular to an external pressure testing device and method based on simulating loading of side soil pressure of a concrete box culvert. Background Art

[0002] Concrete box culverts are widely used in sponge cities and integrated pipe corridors. They are an important means for "sponge cities" to achieve water storage and drainage, and are also the main structural form for building integrated pipe corridors. In recent years, with the continuous improvement of underground transportation systems in large and medium-sized cities, the long-term stress and strain effects of box culverts on ground settlement, surrounding buildings, and underground pipelines due to the effect of vehicle loads after they are put into operation cannot be ignored.

[0003] At present, in order to measure the damage of box culverts against external loads, the Ministry of Industry and Information Technology has issued the national industry standard "JC / T 2456-2018 Precast Concrete Box Culverts", which stipulates relevant terms, technical requirements and external pressure test methods. However, the model test devices and methods currently developed only consider the impact of vehicle loads, but do not consider that concrete box culverts are usually buried underground and are under long-term soil pressure, which affects the accuracy of the test results. Summary of the invention

[0004] The main purpose of the present invention is to propose an external pressure test device and method based on simulating the side earth pressure of a concrete box culvert, aiming to solve the above-mentioned problems.

[0005] To achieve the above-mentioned purpose, the present invention proposes an external pressure test device based on simulating the side earth pressure of a loaded concrete box culvert, comprising:

[0006] A base, on which a test station is provided, and the test station is used to place a concrete box culvert;

[0007] A vertical loading assembly, comprising a vertical loading member, wherein the vertical loading member is used to apply a load downward to the concrete box culvert;

[0008] A lateral loading assembly, comprising a first reaction beam, a second reaction beam and an elastic member, wherein the first reaction beam and the second reaction beam are respectively arranged on both sides of the concrete box culvert in a first direction, the elastic member is arranged on a side of the first reaction beam facing the concrete box culvert, the position of the first reaction beam in the first direction is adjustable, and is used to act on the elastic member to apply a load to the concrete box culvert along the first direction, and the second reaction beam is used to abut against the concrete box culvert; and,

[0009] A first pressure sensor is provided on the vertical loading member, and is used to measure an actual crack load value and an actual failure load value of the concrete box culvert when the vertical loading member applies a load to the concrete box culvert;

[0010] Wherein, the first direction is perpendicular to the up-down direction.

[0011] Further, the elastic member is extended along the first direction, has a first end and a second end, and the first end is connected to the first reaction beam;

[0012] The side loading assembly further comprises:

[0013] a connecting member, disposed at the second end of the elastic member and used for abutting against the concrete box culvert; and,

[0014] The second pressure sensor is used to measure the pressure exerted by the first reaction beam on the elastic member.

[0015] Furthermore, the side loading assembly further comprises a transmission member, and the transmission member is arranged at the first end of the elastic member;

[0016] The second pressure sensor is arranged between the transmission member and the first reaction beam.

[0017] Furthermore, the side loading assembly further includes a guide rod, which is extended along the first direction, sleeved in the elastic member, and connected to the connecting member.

[0018] Furthermore, the side loading assembly further comprises:

[0019] A housing is provided on a side of the first reaction beam facing the concrete box culvert and is extended along the first direction, a side wall of the housing away from the first direction beam is penetrated with an avoidance hole, the elastic member and the second pressure sensor are provided in the housing, and the connecting member is inserted into the avoidance hole and connected to the second end of the elastic member; and,

[0020] The limiting sleeve is extended along the first direction, is arranged on a side of the housing away from the first direction beam, and is sleeved on the outer periphery of the connecting member.

[0021] Furthermore, the side loading assembly further comprises:

[0022] A first loading longitudinal beam is provided between the connecting member and the concrete box culvert; and

[0023] The second loading longitudinal beam is arranged between the second reaction beam and the concrete box culvert.

[0024] Furthermore, the side loading assembly further comprises a first adjusting assembly and a second adjusting assembly, wherein the first adjusting assembly and the second adjusting assembly are respectively arranged on both sides of the concrete box culvert in the second direction;

[0025] The first adjustment assembly includes two first steel beams, the two first steel beams are respectively extended along the first direction and spaced apart along the up-down direction, one end of the two first steel beams penetrates the first reaction beam, is threadedly connected to the first reaction beam, and is fixed by a nut, and the other end of the two first steel beams penetrates the second reaction beam, is threadedly connected to the second reaction beam, and is fixed by a nut;

[0026] The second adjustment assembly includes two second steel beams, the two second steel beams are respectively extended along the first direction and spaced apart along the up-down direction, one end of the two second steel beams penetrates the first reaction beam, is threadedly connected to the first reaction beam, and is fixed by nuts, and the other ends of the two second steel beams penetrates the second reaction beam, is threadedly connected to the second reaction beam, and is fixed by nuts;

[0027] The second direction, the first direction and the up-down direction are perpendicular to each other.

[0028] Further, the vertical loading assembly includes a first column, a second column and a loading beam, the first column and the second column are respectively arranged on both sides of the test station in the first direction, and are respectively extended along the up and down directions, the loading beam is located between the first column and the second column, is extended along the first direction, and is connected to the first column and the second column, and the position of the loading beam in the up and down directions is adjustable;

[0029] The vertical loading member is arranged on the loading beam.

[0030] Further, the test station is provided with at least two lower support beams, the two lower support beams are arranged in sequence along the first direction, for placing the concrete box culvert, and each of the lower support beams can move relative to the base along the first direction; and / or,

[0031] An upper support beam is provided at the lower side of the vertical loading member.

[0032] The present invention also provides an external pressure test method based on simulating the soil pressure on the side of a concrete box culvert, which is applicable to an external pressure test device based on simulating the soil pressure on the side of a concrete box culvert. The external pressure test method based on simulating the soil pressure on the side of a concrete box culvert comprises the following steps:

[0033] Step S1, placing the concrete box culvert on the test station of the base;

[0034] Step S2, calculating the average soil pressure on the side wall of the concrete box culvert when it is buried underground to obtain a preset load;

[0035] Step S3, applying a load to the concrete box culvert along a first direction using a first reaction beam, a second reaction beam, and an elastic member, and adjusting the load applied by the elastic member according to a measurement result of the first pressure sensor until the measurement result of the first pressure sensor reaches the preset load;

[0036] Step S4, controlling the vertical loading member to apply load downward to the concrete box culvert in stages, and measuring the load applied by the vertical loading member to the concrete box culvert in real time through the first pressure sensor until cracks appear on the concrete box culvert, and the crack width is equal to or greater than a preset width value, and obtaining the actual crack load value of the concrete box culvert according to the measurement result of the first pressure sensor;

[0037] Step S5, controlling the vertical loading component to apply loads downward in stages to the concrete box culvert, and measuring the loads applied by the vertical loading component to the concrete box culvert in real time through the first pressure sensor until the concrete box culvert is destroyed, and obtaining the actual destruction load value of the concrete box culvert according to the measurement result of the first pressure sensor.

[0038] In the technical solution of the present invention, the vertical loading member applies a load downward to the concrete box culvert to simulate the application of long-term surface traffic loads to the concrete box culvert, and the lateral loading assembly applies a load to the concrete box culvert along the first direction to simulate the application of soil pressure. The actual crack load value and the actual failure load value of the concrete box culvert are measured by the first pressure sensor. Compared with the existing test device, it can be closer to the actual engineering situation and improve the accuracy of the test results, thereby ensuring that the concrete box culvert has higher safety in actual engineering use. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0040] Figure 1 A front view of an embodiment of an external pressure test device based on simulating the earth pressure on the side of a concrete box culvert provided by the present invention;

[0041] Figure 2 for Figure 1 Side view of the external pressure test device based on simulating the side earth pressure of the concrete box culvert;

[0042] Figure 3 for Figure 1A partial structural diagram of the external pressure test device based on simulating the earth pressure on the side of the concrete box culvert;

[0043] Figure 4 A flow chart of an external pressure test method based on simulating the earth pressure on the side of a concrete box culvert provided by the present invention.

[0044] Description of Figure Numbers:

[0045]

[0046] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0047] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0048] It should be noted that if the embodiments of the present invention involve directional indications (such as up, down, left, right, front, back, etc.), the directional indications are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0049] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the meaning of "and / or" appearing in the full text includes three parallel schemes. Taking "A and / or B" as an example, it includes scheme A, or scheme B, or a scheme that satisfies both A and B. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in the field to implement. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0050] Concrete box culverts are widely used in sponge cities and integrated pipe corridors. They are an important means for "sponge cities" to achieve water storage and drainage, and are also the main structural form for building integrated pipe corridors. In recent years, with the continuous improvement of underground transportation systems in large and medium-sized cities, the long-term stress and strain effects of box culverts on ground settlement, surrounding buildings, and underground pipelines due to the effect of vehicle loads after they are put into operation cannot be ignored.

[0051] At present, in order to measure the damage of box culverts against external loads, the Ministry of Industry and Information Technology has issued the national industry standard "JC / T 2456-2018 Precast Concrete Box Culverts", which stipulates relevant terms, technical requirements and external pressure test methods. However, the model test devices and methods currently developed only consider the impact of vehicle loads, but do not consider that concrete box culverts are usually buried underground and are under long-term soil pressure, which affects the accuracy of the test results.

[0052] In view of this, the present invention provides an external pressure test device 100 based on simulating the earth pressure on the side of a concrete box culvert. Figures 1 to 3 An embodiment of an external pressure test device 100 provided by the present invention based on simulating the earth pressure on the side of a concrete box culvert.

[0053] See also Figures 1 to 3 The external pressure test device 100 based on simulating the lateral soil pressure of the concrete box culvert includes a base 1, a vertical loading component 2, a lateral loading component 3 and a first pressure sensor 4. The base 1 is provided with a test station, and the test station is used to place the concrete box culvert; the vertical loading component 2 includes a vertical loading member 21, and the vertical loading member 21 is used to apply a load downward to the concrete box culvert; the lateral loading component 3 includes a first reaction beam 31, a second reaction beam 32 and an elastic member 33, and the first reaction beam 31 and the second reaction beam 32 are respectively arranged at two sides of the concrete box culvert in the first direction. side, the elastic member 33 is arranged on the side of the first reaction beam 31 facing the concrete box culvert 200, the position of the first reaction beam 31 in the first direction is adjustable, and is used to act on the elastic member 33 to apply a load to the concrete box culvert along the first direction, and the second reaction beam 32 is used to abut against the concrete box culvert 200; the first pressure sensor 4 is arranged on the vertical loading member 21, and is used to measure the actual crack load value and the actual destruction load value of the concrete box culvert when the vertical loading member 21 applies a load to the concrete box culvert; wherein, the first direction is perpendicular to the up and down directions.

[0054] In the technical solution of the present invention, the vertical loading member 21 applies a load downward to the concrete box culvert to simulate the application of long-term surface vehicle loads to the concrete box culvert, and the lateral loading assembly 3 applies a load to the concrete box culvert along the first direction to simulate the application of soil pressure. The actual crack load value and the actual failure load value of the concrete box culvert are measured by the first pressure sensor 4. Compared with the existing test device, it can be closer to the actual engineering conditions and improve the accuracy of the test results, thereby ensuring that the concrete box culvert has higher safety in actual engineering use.

[0055] It should be noted that, in the present invention, the magnitude of the load applied by the elastic member 33 to the concrete box culvert is used to simulate the depth of the concrete box culvert buried in the ground. At the same time, the first reaction beam 31, the second reaction beam 32 and the elastic member 33 are all arranged corresponding to the middle part of the force-bearing side wall of the concrete box culvert, so that the concrete box culvert is evenly stressed.

[0056] It should also be noted that, in the present invention, by adjusting the position of the first reaction beam 31 in the first direction, it is possible to achieve that the elastic member 33 is subjected to force to act on the concrete box culvert, and the load value applied by the elastic member 33 can be adjusted. In addition, the lateral loading assembly 3 can be applicable to concrete box culverts of various sizes and models for testing.

[0057] It should be noted that, in the present invention, the arrangement form of the elastic member 33 is not limited, and it can be a spring, or an elastic member 33 such as a rubber member. Figure 3 In one embodiment of the present invention, the elastic member 33 is a spring. Further, by selecting springs with different stiffness coefficients, the concrete box culvert can be simulated to be buried in different types of soil.

[0058] It should also be noted that, in one embodiment of the present invention, the vertical loading member 21 is a jack.

[0059] For further information, see Figure 3 The elastic member 33 is extended along the first direction and has a first end and a second end, wherein the first end is connected to the first reaction beam 31; the lateral loading assembly 3 further includes a connecting member 34 and a second pressure sensor 35, wherein the connecting member 34 is provided at the second end of the elastic member 33 and is used to abut against the concrete box culvert; the second pressure sensor 35 is used to measure the pressure exerted by the first reaction beam 31 on the elastic member 33. In this way, the load applied by the elastic member 33 to the concrete box culvert can be adjusted according to the measurement result of the second pressure sensor 35 to simulate soil pressures of different magnitudes.

[0060] For details, please refer to Figure 3 The lateral loading assembly 3 further includes a transmission member 36, which is disposed at the first end of the elastic member 33; the second pressure sensor 35 is disposed between the transmission member 36 and the first reaction beam 31. More specifically, in one embodiment of the present invention, the transmission member 36 is an iron block with a certain rigidity, which is used to transmit the load of the first reaction beam 31 to the elastic member 33, so that the elastic member 33 is compressed.

[0061] For details, please refer to Figure 3 The lateral loading assembly 3 further includes a guide rod 37, which is extended along the first direction, sleeved in the elastic member 33, and connected to the connecting member 34. The guide rod 37 has a guiding function to prevent the elastic suction member from bending under force and affecting load transfer.

[0062] For details, please refer to Figure 1 and Figure 3 The lateral loading assembly 3 further includes a housing 38 and a limiting sleeve 39. The housing 38 is disposed on the side of the first reaction beam 31 facing the concrete box culvert and is extended along the first direction. A side wall of the housing 38 away from the first direction beam is penetrated with an avoidance hole. The elastic member 33 and the second pressure sensor 35 are disposed in the housing 38. The connecting member 34 is inserted in the avoidance hole and connected to the second end of the elastic member 33. The limiting sleeve 39 is extended along the first direction and is disposed on the side of the housing 38 away from the first direction beam and is sleeved on the outer periphery of the connecting member 34. In this way, the movable direction of the connecting member 34 is limited by the limiting sleeve 39, so that the connecting member 34 can only be subjected to the force of the elastic member 33 moving along the first direction.

[0063] Specifically, since the elastic member 33 directly applies a point load to the concrete box culvert, please refer to Figures 1 to 3 The lateral loading assembly 3 also includes a first loading longitudinal beam 3A and a second loading longitudinal beam 3B. The first loading longitudinal beam 3A is arranged between the connecting member 34 and the concrete box culvert; the second loading longitudinal beam 3B is arranged between the second reaction beam 32 and the concrete box culvert; in this way, the load transmitted to the concrete box culvert through the first loading longitudinal beam 3A is a uniformly distributed load.

[0064] More specifically, in one embodiment of the present invention, the first loading longitudinal beam 3A and the second loading longitudinal beam 3B have the same size and material, and are parallel to the first reaction beam 31 .

[0065] For details, please refer to Figure 1 and Figure 2The lateral loading assembly 3 also includes a first adjustment assembly and a second adjustment assembly, and the first adjustment assembly and the second adjustment assembly are respectively arranged on both sides of the concrete box culvert in the second direction; the first adjustment assembly includes two first steel beams 3C, the two first steel beams 3C are respectively extended along the first direction, and are spaced along the up-down direction, one end of the two first steel beams are both penetrated through the first reaction beam 31, and are threadedly connected to the first reaction beam 31, and are fixed by nuts, and the other ends of the two first steel beams are both penetrated through the second reaction beam 32, and are threadedly connected to the second reaction beam 32, and are fixed by nuts; the second adjustment assembly includes two second steel beams 3D, the two second steel beams 3D are respectively extended along the first direction, and are spaced along the up-down direction, one end of the two second steel beams are both penetrated through the first reaction beam 31, and are threadedly connected to the first reaction beam 31, and are fixed by nuts, and the other ends of the two second steel beams are both penetrated through the second reaction beam 32, and are threadedly connected to the second reaction beam 32, and are fixed by nuts; wherein, the second direction, the first direction and the up-down direction are mutually perpendicular.

[0066] In this way, the position of the first reaction beam 31 and / or the second reaction beam 32 can be adjusted by rotating the first steel beam 3C and the second steel beam 3D, thereby acting on the elastic member 33, and at the same time, the spacing between the first reaction beam 31 and the second reaction beam 32 can be adjusted to be suitable for concrete box culvert tests of different sizes, thereby improving practicality.

[0067] More specifically, in one embodiment of the present invention, the first reaction beam 31 and the second reaction beam 32 are both provided with screw holes, and both ends of the first steel beam 3C and both ends of the second steel beam 3D are both provided with threads matching the screw holes, so that the first steel beam 3C and the second steel beam 3D are threadedly connected to the first reaction beam 31 and the second reaction beam 32 respectively.

[0068] For details, please refer to Figure 1 and Figure 2The vertical loading assembly 2 includes a first column 22, a second column 23 and a loading beam 24. The first column 22 and the second column 23 are respectively arranged on both sides of the test station in the first direction and are respectively extended along the up-down direction. The loading beam 24 is located between the first column 22 and the second column 23, is extended along the first direction, and is connected to the first column 22 and the second column 23. The position of the loading beam 24 in the up-down direction is adjustable. The vertical loading member 21 is arranged on the loading beam 24. In this way, the position adjustment of the vertical loading member 21 is realized by adjusting the position of the loading beam 24, so as to be applicable to concrete box culvert tests of different sizes and improve practicality.

[0069] Please note that Figure 1 and Figure 2 In the present invention, the vertical loading member 21 is disposed in the middle of the loading beam 24. More specifically, in the present invention, the connection method between the vertical loading member 21 and the loading beam 24 is not limited, and can be welding, threaded connection, etc.

[0070] Furthermore, a plurality of threaded assembly holes are distributed in an array on the first column 22 and the second column 23, and bolts are inserted into both ends of the loading beam 24 so as to be threadedly connected to one of the threaded assembly holes according to the size of the concrete box culvert, thereby realizing the position adjustment of the loading beam 24 in the up and down directions, thereby realizing the position adjustment of the vertical loading member 21.

[0071] Specifically, in one embodiment of the present invention, the loading beam 24 is an H-shaped steel.

[0072] Specifically, at least one lower support beam 5 is provided on the test station, and the lower support beam 5 is used to place the concrete box culvert, and the lower support beam 5 can move along the first direction relative to the base 1. In this way, by moving at least one of the lower support beams 5 in the first direction, the distance between the two lower support beams 5 can be adjusted, so that concrete box culverts of different sizes can be placed for testing.

[0073] Specifically, an upper support beam 6 is provided at the lower side of the vertical loading member 21 .

[0074] It should be noted that, in the present invention, the above two technical features can be set either one or both. For details, please refer to Figure 1 and Figure 2In one embodiment of the present invention, the above two technical features are provided at the same time, that is, at least one lower support beam 5 is provided on the test station, and the lower support beam 5 is used to place the concrete box culvert, and the lower support beam 5 can move along the first direction relative to the base 1. In this way, at least one lower support beam 5 moves in the first direction, and an upper support beam 6 is provided on the lower side of the vertical loading member 21.

[0075] For further information, see Figure 1 and Figure 2 In one embodiment of the present invention, at least one embedded slide rail 7 is provided on the test station, and the embedded slide rail 7 extends along the first direction. The lower support beam 5 is slidably installed on the embedded slide rail 7 so as to be movable relative to the base 1 along the first direction.

[0076] It should be noted that, in the present invention, the number of the lower support beams 5 and the embedded slide rails 7 is not limited. Specifically, in one embodiment of the present invention, two embedded slide rails 7 and two lower support beams 5 are provided on the test station, and the two embedded slide rails 7 are spaced apart along the second direction, and each lower support beam 5 is slidably installed on the two embedded slide rails 7.

[0077] For further information, see Figure 1 and Figure 2 A first rubber pad 8 is bonded between the lower support beam 5 and the concrete box culvert, and a second rubber pad 9 is bonded between the upper support beam 6 and the concrete box culvert.

[0078] Specifically, in one embodiment of the present invention, the lower support beam 5 and the upper support beam 6 are both H-shaped steels.

[0079] Specifically, in an embodiment of the present invention, the first reaction beam 31 and the second reaction beam 32 are both H-shaped steels.

[0080] The present invention also provides an external pressure test method based on simulating the soil pressure on the side of a concrete box culvert, which is applicable to the external pressure test device based on simulating the soil pressure on the side of a concrete box culvert as described above. Figure 4 The external pressure test method based on simulating the side earth pressure of the concrete box culvert includes the following steps:

[0081] Step S1, placing the concrete box culvert on the test station of the base.

[0082] In this step, the size of the concrete box culvert to be measured is measured, and according to its length in the first direction, the distance between the two lower supporting beams is adjusted on the embedded slide rail, and the concrete box culvert is placed on the first rubber pad of the lower supporting beam; the position of the loading beam in the up and down directions is adjusted so that the second rubber pad on the vertical loading member abuts against the upper surface of the concrete box culvert; the lateral loading assembly is assembled on the periphery of the concrete box culvert.

[0083] Step S2, calculating the average soil pressure on the side wall of the concrete box culvert when it is buried underground to obtain a preset load.

[0084] Step S3: Use the first reaction beam, the second reaction beam and the elastic member to apply a load to the concrete box culvert along a first direction, and adjust the load applied by the elastic member according to the measurement result of the first pressure sensor until the measurement result of the first pressure sensor is the preset load.

[0085] In this step, the magnitude of the load applied by the elastic member to the concrete box culvert is adjusted according to the measurement result of the first pressure sensor to simulate the soil pressure on the concrete box culvert when buried underground.

[0086] Step S4, controlling the vertical loading member to apply load downward in stages to the concrete box culvert, and measuring the load applied by the vertical loading member to the concrete box culvert in real time through the first pressure sensor until cracks appear on the concrete box culvert and the crack width is equal to or greater than a preset width value, and obtaining the actual crack load value of the concrete box culvert according to the measurement result of the first pressure sensor.

[0087] In this step, the vertical loading member is controlled to apply load at a loading speed of 30 kN / (m*min).

[0088] More specifically, first apply load from zero to 80% of the specified crack load value, and then apply load in stages at 20% of the specified crack load value, maintaining the load for 1 minute at each stage, and observe whether there are cracks. If there are cracks, measure the crack width with a reading microscope and a feeler gauge. Then continue to apply load in stages at 10% of the specified crack load value, maintaining the load for 1 minute at each stage. After loading to the specified crack load value, maintain the specified crack load for 3 minutes, and measure the crack width again. Then, when the crack width is measured to be less than 0.02 mm, continue to apply load in stages at 5% of the specified crack load value, maintaining the load for 3 minutes at each stage, until the crack width is equal to or greater than the preset width value (0.02 mm).

[0089] It should be noted that, at the end of loading, the crack width is equal to the preset width value, and the actual crack load value of the concrete box culvert is the load value of this level; at the end of loading, the crack width is greater than the preset width value, and the actual crack load value of the concrete box culvert is the load value of the previous level.

[0090] Step S5, controlling the vertical loading component to apply loads downward in stages to the concrete box culvert, and measuring the loads applied by the vertical loading component to the concrete box culvert in real time through the first pressure sensor until the concrete box culvert is destroyed, and obtaining the actual destruction load value of the concrete box culvert according to the measurement result of the first pressure sensor.

[0091] In this step, the vertical loading member is controlled to continue applying the load at a loading speed of 30 kN / (m*min).

[0092] More specifically, continue to apply load to 80% of the specified failure load value, maintain the load for 1 minute, and observe whether there is any damage; if there is no damage, continue to apply load in stages according to 10% of the specified failure load value, maintain the load for 1 minute at each stage, and after loading to the specified failure load value, maintain the load for 3 minutes and check for damage; if there is no damage, continue to apply load in stages according to 5% of the specified failure load value, maintain the load for 3 minutes at each stage, until the concrete box culvert is damaged.

[0093] It should be noted that the load when the box culvert loses its bearing capacity is the destruction load. During the loading process, when the concrete box culvert is in a state of destruction, the actual destruction load value is the previous level load; when the destruction state occurs within the specified load duration, the actual destruction load value is the average of this level load and the previous level load; when the destruction state occurs after the specified load duration ends, the actual destruction load value is the load value of this level.

[0094] The above description is only a preferred embodiment of the present invention, and does not limit the patent scope of the present invention. All equivalent structural changes made by using the contents of the present invention specification and drawings under the inventive concept of the present invention, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. An external pressure test device based on simulating the side earth pressure of a concrete box culvert, characterized in that: The external pressure test device based on simulating the side earth pressure of the loaded concrete box culvert comprises: A base, on which a test station is provided, and the test station is used to place a concrete box culvert; A vertical loading assembly, comprising a vertical loading member, wherein the vertical loading member is used to apply a load downward to the concrete box culvert; A lateral loading assembly, comprising a first reaction beam, a second reaction beam and an elastic member, wherein the first reaction beam and the second reaction beam are respectively arranged on both sides of the concrete box culvert in a first direction, the elastic member is arranged on a side of the first reaction beam facing the concrete box culvert, the position of the first reaction beam in the first direction is adjustable, and is used to act on the elastic member to apply a load to the concrete box culvert along the first direction, and the second reaction beam is used to abut against the concrete box culvert; and, A first pressure sensor is provided on the vertical loading member, and is used to measure an actual crack load value and an actual failure load value of the concrete box culvert when the vertical loading member applies a load to the concrete box culvert; Wherein, the first direction is perpendicular to the up-down direction.

2. The external pressure test device based on simulating the side earth pressure of the concrete box culvert as claimed in claim 1 is characterized in that: The elastic member is extended along the first direction and has a first end and a second end, and the first end is connected to the first reaction beam; The side loading assembly further comprises: a connecting member, disposed at the second end of the elastic member and used for abutting against the concrete box culvert; and, The second pressure sensor is used to measure the pressure exerted by the first reaction beam on the elastic member.

3. The external pressure test device based on simulating the side earth pressure of the concrete box culvert as claimed in claim 2 is characterized in that: The side loading assembly further includes a transmission member, and the transmission member is disposed at the first end of the elastic member; The second pressure sensor is arranged between the transmission member and the first reaction beam.

4. The external pressure test device based on simulating the earth pressure on the side of the concrete box culvert as claimed in claim 2 is characterized in that: The side loading assembly further includes a guide rod, which is extended along the first direction, sleeved in the elastic member, and connected to the connecting member.

5. The external pressure test device based on simulating the side earth pressure of the concrete box culvert as claimed in claim 2 is characterized in that: The side loading assembly further comprises: A housing is provided on a side of the first reaction beam facing the concrete box culvert and is extended along the first direction, a side wall of the housing away from the first direction beam is penetrated with an avoidance hole, the elastic member and the second pressure sensor are provided in the housing, and the connecting member is inserted into the avoidance hole and connected to the second end of the elastic member; and, The limiting sleeve is extended along the first direction, is arranged on a side of the housing away from the first direction beam, and is sleeved on the outer periphery of the connecting member.

6. The external pressure test device based on simulating the earth pressure on the side of the concrete box culvert as claimed in claim 2 is characterized in that: The side loading assembly further comprises: A first loading longitudinal beam is provided between the connecting member and the concrete box culvert; and The second loading longitudinal beam is arranged between the second reaction beam and the concrete box culvert.

7. The external pressure test device based on simulating the side earth pressure of a concrete box culvert as claimed in claim 1 is characterized in that: The side loading assembly further includes a first adjustment assembly and a second adjustment assembly, wherein the first adjustment assembly and the second adjustment assembly are respectively arranged on both sides of the concrete box culvert in the second direction; The first adjustment assembly includes two first steel beams, the two first steel beams are respectively extended along the first direction and spaced apart along the up-down direction, one end of the two first steel beams penetrates the first reaction beam, is threadedly connected to the first reaction beam, and is fixed by a nut, and the other end of the two first steel beams penetrates the second reaction beam, is threadedly connected to the second reaction beam, and is fixed by a nut; The second adjustment assembly includes two second steel beams, the two second steel beams are respectively extended along the first direction and spaced apart along the up-down direction, one end of the two second steel beams penetrates the first reaction beam, is threadedly connected to the first reaction beam, and is fixed by nuts, and the other ends of the two second steel beams penetrates the second reaction beam, is threadedly connected to the second reaction beam, and is fixed by nuts; The second direction, the first direction and the up-down direction are perpendicular to each other.

8. The external pressure test device based on simulating the side earth pressure of a concrete box culvert as claimed in claim 1 is characterized in that: The vertical loading assembly includes a first column, a second column and a loading beam, the first column and the second column are respectively arranged on both sides of the test station in the first direction, and are respectively extended along the up and down directions, the loading beam is located between the first column and the second column, is extended along the first direction, and is connected to the first column and the second column, and the position of the loading beam in the up and down directions is adjustable; The vertical loading member is arranged on the loading beam.

9. The external pressure test device based on simulating the side earth pressure of the concrete box culvert as claimed in claim 8, characterized in that: The test station is provided with at least two lower support beams, which are arranged in sequence along the first direction for placing the concrete box culvert, and each of the lower support beams can move relative to the base along the first direction; and / or, An upper support beam is provided at the lower side of the vertical loading member.

10. An external pressure test method based on simulating the soil pressure on the side of a concrete box culvert, applicable to the external pressure test device based on simulating the soil pressure on the side of a concrete box culvert as described in any one of claims 1 to 9, characterized in that: The external pressure test method based on simulating the side earth pressure of the loaded concrete box culvert comprises the following steps: Step S1, placing the concrete box culvert on the test station of the base; Step S2, calculating the average soil pressure on the side wall of the concrete box culvert when it is buried underground to obtain a preset load; Step S3, applying a load to the concrete box culvert along a first direction using a first reaction beam, a second reaction beam, and an elastic member, and adjusting the load applied by the elastic member according to a measurement result of the first pressure sensor until the measurement result of the first pressure sensor reaches the preset load; Step S4, controlling the vertical loading member to apply load downward to the concrete box culvert in stages, and measuring the load applied by the vertical loading member to the concrete box culvert in real time through the first pressure sensor until cracks appear on the concrete box culvert, and the crack width is equal to or greater than a preset width value, and obtaining the actual crack load value of the concrete box culvert according to the measurement result of the first pressure sensor; Step S5, controlling the vertical loading component to apply loads downward in stages to the concrete box culvert, and measuring the loads applied by the vertical loading component to the concrete box culvert in real time through the first pressure sensor until the concrete box culvert is destroyed, and obtaining the actual destruction load value of the concrete box culvert according to the measurement result of the first pressure sensor.

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