Device and method for testing influence of blasting on existing cracks of building

Abstract

The invention relates to the technical field of building structure vibration tests, and provides a device and method for testing the influence of blasting on existing cracks of a building, and the device comprises a subbase structure, a house wall body, a ring beam, a hole lintel and a roof panel, a brick foundation is laid on a cushion layer, and the house wall body is built on the brick foundation. A crack is formed in the house wall in the thickness direction of the house wall, identification blocks are symmetrically arranged on the two sides of the crack, opening lintels are arranged on the tops of window openings or door openings, ring beams are arranged on the top of the house wall, and roof panels are arranged on the ring beams. The test method comprises the following steps: selecting a test site; a test house is built, hole lintels are placed on window holes and door holes of house walls, ring beams and roof panels are sequentially placed on the tops of the house walls, and finally the surface of the house is plastered; prefabricating test cracks; the test device is easy to build, low in manufacturing cost, easy to operate, convenient and fast, and the influence of blasting on the existing cracks of the building can be visually, efficiently and truly simulated through the test device.

Description

Technical Field

[0001] The present invention relates to the technical field of building structure vibration tests, and particularly to a test device and a test method for the influence of blasting on existing cracks in buildings. Background Technique

[0002] With the continuous expansion of the scale of urban construction, new buildings will inevitably be constructed in densely built-up areas. Existing buildings around the construction area have different degrees of crack damage in their structures due to many reasons such as long service life, weakened material strength, and uneven foundation settlement.

[0003] During the blasting construction process, the existing crack damage in different houses may produce different vibration responses to the same blasting vibration. Especially for the damaged parts that have already cracked, adjacent blasting construction may cause unstable expansion of the cracks, seriously endangering the reliability of the existing crack structure of masonry buildings and making it impossible to scientifically judge the influence of blasting vibration on the existing damage of houses when civil litigation issues occur. The cracking of houses involves the vital interests of residents. If this problem is not handled well in actual projects, it is very easy to escalate from a simple technical problem to a complex economic problem and social stability problem, with serious negative impacts. Therefore, in view of the above problems, a test device and a test method for the influence of blasting on existing cracks in buildings are proposed to solve the above problems. Summary of the Invention

[0004] In view of the deficiencies of the prior art, the present invention develops a test device and a test method for the influence of blasting on existing cracks in buildings. The structure of the present invention is simple and the operation is convenient, and the change in crack width can be measured intuitively.

[0005] The technical solution for the present invention to solve the technical problem is: The present invention provides a test device for the influence of blasting on existing cracks in buildings, including a base structure, a house wall, a ring beam, a lintel for the opening, and a roof slab. The base structure includes a cushion layer, a brick foundation, and wall piers. The cushion layer is a concrete cushion layer, on which the brick foundation is laid. Wall piers are provided at the four corners of the room in the brick foundation. The house wall is built on the brick foundation, and cracks are opened along the thickness direction of the house wall. Identification blocks are symmetrically arranged on both sides of the cracks. Among them, window openings and door openings are respectively opened on two adjacent house walls, and lintels for the openings are provided at the top of the window openings or door openings. A ring beam is provided at the top of the house wall, and a roof slab is provided on the ring beam.

[0006] As an optimization, the ring beam is in the shape of a square frame, two roof slabs are provided, and lifting rings are arranged on the roof slabs.

[0007] A test method for the influence of blasting on existing cracks in buildings, applicable to the test device described in any one of the above, includes the following steps: S1: Selection of the test site; S2: Test house construction: First, build the foundation structure, then build the house walls, place lintels over the window and door openings on the house walls, then place ring beams and roof panels on top of the house walls, and finally plaster the house surface; S3: experimental crack prefabrication; S4: Crack detection.

[0008] As an optimization, in S2, a house cushion layer and a brick foundation were built according to the size of the test house. C20 shotcrete was used to cast the house cushion layer, and then bricks were laid to form a brick foundation. Concrete with a thickness of 300mm was poured around the brick foundation. The thickness of the house wall was 120mm, and buttresses were set at the four corners of the house wall.

[0009] The wall size is 240mm×240mm.

[0010] As an optimization, in S2, the ring beam is pre-embedded with a lifting hook, and the hook on the ring beam is placed face down on the wall of the house, and the ring beam and the roof panel are connected with mortar.

[0011] As an optimization, during the construction of the house walls, the mortar joint locations are selected and steel plates are placed. The positions of the steel plates are the crack locations. After curing, the steel plates are pulled out to form prefabricated cracks.

[0012] As an optimization, in S4, crack detection includes laying out vibration meters, sticking identification blocks on both sides of the cracks, and measuring the crack width. Vibration meters are laid out at the two corners of the test house to monitor the vibration velocity caused by blasting construction. Monitoring points are selected at the prefabricated cracks, and identification blocks are stuck on both sides of the monitoring points. The measurement position is marked on the identification blocks, and the measurement position is measured using a vernier caliper.

[0013] As an optimization, three monitoring points are selected at each prefabricated crack, and an identification block is pasted at each monitoring point.

[0014] The effects provided in the summary of the invention are only the effects of the embodiments, rather than all the effects of the invention. The above technical solution has the following advantages or beneficial effects: 1. This test device is simple to build, low in cost, and easy to operate. By setting up this test device, the impact of blasting on existing cracks in buildings can be realistically simulated; 2. This test method is simple. By clamping a vernier caliper on both sides of the marking block, when blasting vibration occurs, the crack changes, and the distance between the marking blocks on both sides of the crack also changes. By observing the size changes of the vernier caliper, the impact of blasting on the existing cracks in the building can be monitored. This test method is more intuitive, efficient, convenient and quick. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The accompanying drawings are used to provide further understanding of the present invention and constitute a part of the specification. They are used to explain the present invention together with the embodiments of the present invention and do not constitute a limitation of the present invention.

[0016] Figure 1 Schematic diagram of the overall structure of the test device of the present invention; Figure 2 is a cross-sectional view of the base structure of the present invention; Figure 3 This is a front view of the ring beam of the present invention; Figure 4 This is a front view of the roof panel of the present invention; Figure 5 is a plan view of the base structure of the present invention; Figure 6 It is the front view of the present invention; Figure 7 It is a left side view of the present invention; Figure 8 For the present invention Figure 1 Enlarged view of point A in the middle.

[0017] In the figure, 1. House wall; 2. Ring beam; 3. Opening lintel; 4. Roof panel; 5. Window opening; 6. Door opening; 8. Brick foundation; 9. Buttress; 10. Lifting ring; 11. Identification block. DETAILED DESCRIPTION

[0018] To clearly illustrate the technical features of this solution, the present invention is described in detail below through specific embodiments and in conjunction with the accompanying drawings. The following disclosure provides numerous different embodiments or examples for implementing various configurations of the present invention. To simplify the disclosure of the present invention, the following description focuses on components and configurations of specific examples. Furthermore, reference numbers and / or letters may be repeated throughout the various examples. This repetition is for the purpose of simplicity and clarity and does not in itself indicate a relationship between the various embodiments and / or configurations discussed. It should be noted that the components illustrated in the drawings are not necessarily drawn to scale. Descriptions of well-known components and processing techniques and processes are omitted to avoid unnecessarily limiting the present invention. Terms such as "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer" indicate positions or locations based on the positions or locations shown in the drawings. These terms are used solely to facilitate the description of the present invention and simplify the description. They are not intended to indicate or imply that the devices or components referred to must have, be constructed, or operate in a specific orientation, and are therefore not to be construed as limiting the present invention. Furthermore, the terms "first," "second," and "third" 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 expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediate medium; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0019] like Figures 1 to 8As shown, a test device for the effect of blasting on existing cracks in a building is shown, comprising a base structure, a house wall 1, a ring beam 2, an opening lintel 3 and a roof panel 4. The base structure comprises a cushion layer, a brick foundation 8 and a wall buttress 9. The cushion layer is a concrete cushion layer, on which a brick foundation 8 is laid. The brick foundation 8 is located at the four corners of the room and wall buttresses 9 are set. The house wall 1 is built on the brick foundation 8. A crack is opened on the house wall 1 along the thickness direction of the house wall 1, and marking blocks 11 are symmetrically arranged on both sides of the crack. Window openings 5 ​​and door openings 6 are respectively opened on two adjacent house walls 1, and an opening lintel 3 is set on the top of the window opening 5 or the door opening 6. A ring beam 2 is set on the top of the house wall 1, and a roof panel 4 is set on the ring beam 2. The dimensions of the roof panel 4 are 2000mm×760mm×60mm, with a margin of 50mm on both sides in the length direction and a margin of 40mm on both sides in the width direction. The panel thickness is 60mm. The panel reinforcement is double-layer, two-way, three-grade steel bars φ8, node binding, longitudinal spacing of 100mm, transverse spacing of 200mm, thickness of the bottom protective layer of the panel is 16mm, thickness of the side protective layer of the panel is 26mm, the dimensions of the opening lintel 3 at the top of the window opening 5 are 710mm×120mm×200mm, and the dimensions of the opening lintel 3 at the top of the door opening 6 are 1000mm×120mm×200mm.

[0020] The test device is simple to build, low in cost, and easy to operate. By setting up the test device, the impact of blasting on existing cracks in buildings can be realistically simulated.

[0021] In this embodiment, Figure 3 and Figure 4 As shown, the ring beam 2 is in the shape of a mesh, two roof panels 4 are provided, and lifting rings 10 are arranged on the roof panels 4. Two lifting rings 10 are symmetrically provided with respect to the length direction of the roof panels, and the distance between the two lifting rings is 1400 mm.

[0022] A test method for the effect of blasting on existing cracks in buildings, applicable to any of the test devices described above, comprising the following steps: S1: Test site selection: Based on the construction organization and construction progress, select a location that will withstand blasting vibration as many times as possible as the test site; S2: Test house construction: First, build the foundation structure, then build the house wall 1. The opening lintel 3, ring beam 2, and roof panel 4 are prefabricated parts. The opening lintel 3 is placed on the window opening 5 and door opening 6 of the house wall 1. The ring beam 2 and roof panel 4 are placed on the top of the house wall 1 in sequence. Finally, the house surface is plastered; S3: Test crack prefabrication; S4: Crack detection.

[0023] In this embodiment, in S2, a house cushion layer is built and a brick foundation 8 is laid according to the size of the test house. C20 sprayed concrete is used to cast the house cushion layer, and then bricks are laid to form a brick foundation 8. Concrete with a thickness of 300 mm is poured around the brick foundation 8. The thickness of the house wall 1 is 120 mm. In order to enhance the stability of the house, buttresses 9 are set at the four corners of the house wall 1.

[0024] The wall buttress 9 has a size of 240 mm x 240 mm.

[0025] In this embodiment, in S2, the ring beam 2 is pre-embedded with a lifting hook. To avoid affecting the placement of the roof panel 4, the hook on the ring beam 2 is placed face down on the house wall 1. The ring beam 2 and the roof panel 4 are connected with mortar, and the mortar thickness is 10 mm.

[0026] In this embodiment, during the construction of the house wall 1, the mortar joint position is selected and the steel plate is placed. Here, a stainless steel plate is selected. The position of the steel plate is the crack position. After curing, the steel plate is pulled out to form a prefabricated crack. The crack is covered with plastic wrap. After curing for one day, the house wall 1 is continued to be built.

[0027] In this embodiment, in S4, crack detection includes laying out vibration meters, sticking identification blocks on both sides of the crack, and measuring the crack width. Vibration meters are laid out at the two corners of the test house to monitor the vibration speed caused by blasting construction. Monitoring points are selected at the prefabricated cracks, and identification blocks 11 are stuck on both sides of the monitoring points. The measurement position is marked on the identification block 11, and the measurement position is measured using a vernier caliper.

[0028] Three monitoring points are selected at each prefabricated crack, and a marking block 11 is pasted at each monitoring point.

[0029] This test method is simple. By clamping a vernier caliper on both sides of the identification block 11, when blasting vibration occurs, the crack changes, and the distance between the identification blocks 11 on both sides of the crack also changes. By observing the size changes of the vernier caliper, the impact of blasting on the existing cracks in the building can be monitored. This test method is more intuitive, efficient, convenient and quick.

[0030] Although the above describes the specific implementation methods of the invention in conjunction with the accompanying drawings, it does not limit the scope of protection of the invention. Based on the technical solution of the present invention, various modifications or variations that can be made by those skilled in the art without creative work are still within the scope of protection of the present invention.

Claims

1. A test device for the effect of blasting on existing cracks in buildings, characterized by: It includes a base structure, a building wall (1), a ring beam (2), a lintel (3) for the opening, and a roof slab (4). The base structure includes a cushion layer, a brick foundation (8), and a wall pier (9). The cushion layer is a concrete cushion layer. The brick foundation (8) is laid on the cushion layer. Wall piers (9) are provided at the four corners of the interior of the brick foundation (8). The building wall (1) is built on the brick foundation (8). Cracks are opened along the thickness direction of the building wall (1). Marking blocks (11) are symmetrically arranged on both sides of the cracks. Among them, window openings (5) and door openings (6) are respectively opened on two adjacent building walls (1). Lintels (3) are provided at the top of the window openings (5) or door openings (6). A ring beam (2) is provided at the top of the building wall (1). A roof slab (4) is provided on the ring beam (2).

2. The test device for the effect of blasting on existing cracks in buildings according to claim 1, characterized in that: The ring beam (2) is in the shape of a square. Two roof slabs (4) are provided, and lifting rings (10) are arranged on the roof slabs (4).

3. A method for testing the effects of blasting on existing cracks in buildings, suitable for use with the test apparatus described in any one of claims 1-2, characterized in that: It includes the following steps S1: Selection of the test site; S2: Construction of the test building. First, the base structure is built, and then the building wall (1) is built. Lintels (3) are placed on the window openings (5) and door openings (6) of the building wall (1). The ring beam (2) and the roof slab (4) are sequentially placed at the top of the building wall (1). Finally, the surface of the building is plastered; S3: Prefabrication of the test cracks; S4: Crack detection.

4. The test method for the effect of blasting on existing cracks in buildings according to claim 3, characterized in that: S2 According to the size of the test building, a building cushion layer is built and the brick foundation (8) is laid. The building cushion layer is poured with C20 shotcrete, and then bricks are laid to form the brick foundation (8). Concrete with a thickness of 300 mm is poured around the brick foundation (8). The thickness of the built building wall (1) is 120 mm. Wall piers (9) are provided at the four corners of the building wall (1).

5. The test method for the effect of blasting on existing cracks in buildings according to claim 4, characterized in that: The size of the wall pier (9) is 240 mm×240 mm.

6. The test method for the influence of blasting on existing cracks in buildings according to claim 3, characterized in that: in S2, lifting hooks for预埋 are provided on the ring beam (2). The hook surface on the ring beam (2) is placed downward on the building wall (1). A mortar connection is used between the ring beam (2) and the roof slab (4).

7. The test method for the effect of blasting on existing cracks in buildings according to claim 3, characterized in that: During the construction of the building wall (1), the position of the mortar joint is selected, and a steel plate is placed. The position of the steel plate is the position of the crack. After curing, the steel plate is pulled out to form a prefabricated crack.

8. The test method for the influence of blasting on existing cracks in buildings according to claim 3, characterized in that: in S4, crack detection includes arranging vibration measuring instruments, pasting marking blocks on both sides of the crack, and measuring the crack width. Vibration measuring instruments are arranged at two corners of the test building to monitor the vibration velocity caused by blasting construction. Monitoring points are selected at the prefabricated cracks. Marking blocks (11) are pasted on both sides of the monitoring points. Measuring positions are marked on the marking blocks (11), and a vernier caliper is used to measure at the measuring positions.

9. The test method for the effect of blasting on existing cracks in buildings according to claim 8, characterized in that: Three monitoring points are selected at each prefabricated crack, and marking blocks (11) are pasted at each monitoring point.

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