Existing building foundation pile quality detection method

Abstract

The invention discloses an existing building foundation pile quality detection method which comprises the following steps: excavating a detection groove along one side of a bearing platform until the bottom of the bearing platform is exposed, and excavating towards the inner side of the bearing platform to expose an existing building foundation pile to form a transfer soil platform; an exploratory well is excavated downwards from the transfer soil platform along one side of the existing building foundation pile; after the exploratory well is excavated to the preset depth every time, a non-closed pile casing is installed for supporting, and a non-closed opening of the non-closed pile casing faces the existing building foundation pile; the quality of the pile body is detected through an unclosed opening of the unclosed pile casing; repeating the steps of mounting the non-closed pile casing and carrying out quality detection until the pile bottom is reached; confirming the position of the pile bottom; the pile length, the pile body perpendicularity and the reinforcement cage length are detected. The integrity of the pile body, the concrete quality, the steel bar condition and the perpendicularity of the pile body can be accurately detected, so that a basis is provided for later foundation reinforcement construction.

Description

Technical Field

[0001] This invention belongs to the field of building foundation quality testing, and relates to a method for testing the quality of existing building foundation piles. Background Technology

[0002] Extensive experience in diagnosing the foundation conditions of existing buildings demonstrates that the quality of pile foundations directly impacts the applicability, durability, and safety of existing buildings using this type of foundation. When existing buildings experience uneven settlement or other issues, and considering subsequent reinforcement options, it is necessary to test the quality of the pile foundations.

[0003] The quality inspection of existing foundation piles includes the integrity of the pile body, the quality of the concrete, the condition of the reinforcing steel, and the verticality of the pile body. Defects in existing building foundation piles, such as broken piles, necking, borehole collapse, excessive verticality deviation, and abnormally large local diameters, can seriously affect the quality of existing foundation piles. Traditional testing techniques for existing foundation pile quality inspection have the following shortcomings: First, existing testing methods are only applicable to the testing of foundation piles for new buildings, and cannot be applied to the continuous quality testing of concealed existing foundation piles under existing buildings.

[0004] Secondly, due to site limitations, large-scale excavation must be avoided for existing buildings. The foundation piles are located below the pile cap 6, making it impossible to directly excavate exploratory wells using machinery such as the Luoyang shovel. Furthermore, such machinery is only suitable for loess strata and is not applicable to non-loess strata (such as sand and gravel layers). Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide a method for testing the quality of existing building foundation piles, which can accurately detect the integrity of the pile body, the quality of the concrete, the condition of the reinforcing steel, and the verticality of the pile body, thereby providing a basis for subsequent foundation reinforcement construction.

[0006] To achieve the above objectives, the present invention employs the following technical solution: A method for testing the quality of existing building foundation piles includes the following steps: Excavate a trench along one side of the foundation to expose the bottom of the foundation, and excavate inward to expose the existing building piles, forming a soil transfer platform; Excavate a test well downwards from the soil transfer platform along one side of the existing building foundation piles; After each exploration well reaches a predetermined depth, an unsealed casing is installed for support, with the unsealed opening of the unsealed casing facing the existing building foundation piles. Quality inspection of the pile body is carried out through the unsealed opening of the non-enclosed casing; Repeat the steps of installing the non-enclosed casing and conducting quality inspections until the bottom of the pile is reached; Confirm the location of the pile bottom; Inspect the pile length, pile verticality, and reinforcement cage length.

[0007] Preferably, before excavating the trench, ground-penetrating radar is used to conduct a preliminary exploration of the area to be excavated to identify the underground pipelines buried in the area to be excavated.

[0008] Preferably, the soil generated during the excavation of the exploratory well is transported out and discharged to the ground through a soil hoisting device set at the wellhead and a soil transfer device set at the trench opening.

[0009] Preferably, the step of installing non-enclosed casing for support is carried out using the reverse construction method.

[0010] Preferably, adjacent upper and lower non-enclosed casings are connected by welding a vertical steel bar; each non-enclosed casing is welded with a horizontal steel bar at intervals.

[0011] Preferably, the steps for quality inspection of the pile body include: using a rebound hammer to test the concrete strength of the pile body; and using a core drilling method to penetrate the existing building foundation piles and test the pile diameter.

[0012] Preferably, the steps for quality inspection of the pile body also include: when encountering a broken pile, detecting the location, crack length, and crack depth of the broken pile; when encountering a localized reduction in the diameter of the pile body, detecting the location and extent of the localized reduction in diameter.

[0013] Preferably, the steps for quality inspection of the pile body also include: when a local enlargement of the pile diameter is encountered, a static expansion agent is embedded to break up the local enlargement of the pile diameter.

[0014] Preferably, the step of confirming the location of the pile bottom includes: excavating downward at an elevation position of the pile bottom and over-excavating radially inward to the inside of the pile bottom; driving a steel bar longer than the diameter of the foundation pile into the radial direction along a horizontal direction below the elevation position of the pile bottom.

[0015] Preferably, the steps for detecting pile length, pile verticality, and reinforcement cage length include: detecting the reinforcement cage length using magnetic measurement; measuring the pile length using direct measurement; and measuring the pile verticality using a verticality meter.

[0016] Compared with the prior art, the present invention has the following beneficial effects: This invention employs a direct method to inspect the integrity of the pile body, the quality of the concrete, the condition of the reinforcing steel, and the verticality of the pile, avoiding the uncertainties arising from non-contact indirect detection methods such as ground-penetrating radar and surface wave methods. The inspection results are detailed and accurate, clearly identifying the specific location and severity of defects along the entire length of the pile. This not only serves for pile inspection but also provides a basis for subsequent reinforcement, assisting engineers in developing reinforcement plans. Compared to methods that directly drill through the pile cap to locate the pile, the latter damages the pile cap, causing significant damage to the existing load-bearing structure, and cannot guarantee that the location of the hole in the pile cap is completely consistent with the location of the existing pile. This invention, by inspecting the integrity of the pile body, the quality of the concrete, the condition of the reinforcing steel, and the verticality of the pile, provides a basis for the reinforcement of existing building foundations, facilitating timely intervention. It overcomes the limitations of traditional inspection methods, including low-strain reflected wave methods, ultrasonic transmission methods, high-strain dynamic testing, and mechanical excavation methods, in detecting the quality of existing building piles. It can accurately detect the integrity of existing building piles, concrete quality, steel reinforcement condition, and pile verticality, thus providing a basis for subsequent foundation reinforcement construction of existing buildings.

[0017] Furthermore, considering the influence of the formation, such as the poor stability of exploration wells in sandy and gravelly formations, casing is used to prevent borehole wall collapse and ensure the safety of operators. Attached Figure Description

[0018] Figure 1 This is a flowchart of the existing building foundation pile quality inspection method according to an embodiment of the present invention; Figure 2 This is a construction schematic diagram of the existing building foundation pile quality inspection method according to an embodiment of the present invention.

[0019] Among them: 1-soil transfer device; 2-soil hoisting device; 3-soil transfer platform; 4-casing; 5-existing building foundation pile; 6-pile cap; 7-partial diameter reduction; 8-partial enlargement; 9-broken pile; 10-pile bottom. Detailed Implementation

[0020] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0021] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of the stated features. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0022] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terms “installation,” “connection,” and “linkage” should be interpreted broadly, for example, as a fixed connection, a detachable connection, or an integral connection; a mechanical connection, an electrical connection, or a connection that allows communication; a direct connection or an indirect connection via an intermediate medium; or a connection within two elements or an interaction between two elements. The term “and / or” as used herein includes any and all combinations of one or more of the associated listed items. Those skilled in the art will understand the specific meaning of the above terms in this invention according to the specific circumstances. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention.

[0023] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0024] The following disclosure provides many different embodiments or examples for implementing various structures of the invention. To simplify the disclosure, specific examples of components and arrangements are described below. These are merely examples and are not intended to limit the invention. Furthermore, reference numerals and / or letters may be repeated in different examples; such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed. In addition, examples of various specific processes and materials are provided in this invention, but those skilled in the art will recognize the application of other processes and / or the use of other materials.

[0025] like Figure 1 and Figure 2 As shown in this embodiment, a method for testing the quality of existing building foundation piles is described. The method includes the following steps: Step 1: Preliminary inspection of the construction trench: Ground-penetrating radar (GPR) was used to conduct a preliminary survey of the area to be excavated for the construction trench, in order to ascertain the preliminary situation of underground pipelines (including power cable trenches, rainwater pipes, and sewage pipes) buried beneath the area. This step involves assessing the impact of underground pipelines on the subsequent trench excavation and outlining corresponding countermeasures.

[0026] Step 2: Installation of Soil Transfer Device 1 First, install the base, then use sandbags to compact the base.

[0027] The soil transfer device 1 includes a base, a robotic arm, a fixed pulley, and a small second winch. The second winch and one end of the robotic arm are connected to the top of the base. The other end of the robotic arm is inclined upward and has a fixed pulley. The cable on the second winch is routed around the fixed pulley along the robotic arm.

[0028] Step 3: Excavation of the construction trench: Step 301: Remove the concrete cushion layer for drainage.

[0029] Step 302: Determine the area of ​​the construction trench. For example, excavate a 3m×3m working platform along the 6 sides of the foundation. In practice, the number of excavators will be increased or decreased based on the results of the preliminary investigation of underground pipelines in Step 1.

[0030] Step 303: Determine the depth of the construction trench. Based on the soil conditions, select appropriate tools (such as shovels, electric picks, or mini grab excavators) and excavate downwards along the side of the foundation 6. Once the bottom of the foundation 6 is exposed, excavate inwards to locate the foundation piles. Continue excavating downwards for approximately 2.0m to complete the construction trench excavation. This forms an "L"-shaped soil transfer platform 3.

[0031] Note: Step 1, the preliminary exploration of the construction trench, has a crucial impact on Step 3, the excavation of the construction trench. Only with sufficient work done in Step 1 can Step 3 proceed smoothly. If underground pipelines are not identified, it will cause problems for the implementation of Step 3, and may even prevent Step 3 and subsequent steps from being carried out. For example, if pipelines are cut during the construction trench excavation, the existing pipelines will restrict the construction trench. In Step 3, the construction trench excavation, since the existing foundation piles are concealed works, the initial location of the foundation piles can only be preliminarily determined based on the drawings, and the exact location of the foundation piles cannot be determined at once. Multiple trial operations are required to determine the location of the foundation piles. In order to ensure that the foundation piles are found, Step 302 generally involves excavating along the entire side of the foundation cap 6.

[0032] Step 4: Install soil lifting device 2: The soil transfer device 1 is used to lift the soil hoisting device 2 from the ground to the soil transfer platform 3. The soil hoisting device 2 is installed according to the location of the exploration well.

[0033] The soil hoisting device 2 includes a tripod and a small first winch, which is located on top of the tripod and the suspension area of ​​the first winch is located directly below the tripod.

[0034] Step 5: Excavation of exploratory wells: Step 501: Excavate downwards along the side 5 of the existing building foundation pile. After each 1m excavation depth, install the casing 4 to support the well wall. The casing 4 is non-enclosed, with the unenclosed opening facing the existing building foundation pile 5. It is horizontally welded with steel bars at equal intervals. Then, (1) use a rebound hammer to test the concrete strength along the pile body. (2) use the core drilling method to drill through the foundation pile and use a tape measure to check the pile diameter. (3) if a broken pile 9 is encountered, use feeler gauges, tape measures, etc. to check the location of the broken pile 9, the length of the crack in the broken pile 9, the depth of the crack, etc. (4) if a local reduction in the diameter of the pile body 7 is encountered, use a ruler, tape measure, etc. to check the location and range of the reduction in diameter. (5) if a local enlargement in the pile diameter 8 is encountered, static expansion agent needs to be buried to break the part of the local enlargement in the pile diameter 8. Because the exploration well is a space-constrained operation area, other methods have requirements on the size of the site, and the static expansion agent will not cause vibration to the surrounding area, which is of great effect on maintaining the stability of the well wall.

[0035] Step 502: After excavating down to the height of another casing 4, for example, 1m, install the new casing 4 to support the well wall. The upper and lower casings 4 are still vertically welded together with steel bars.

[0036] Steps 501 and 502 are performed alternately, using the reverse construction method (a method of constructing underground structures from top to bottom) to support the well wall until the bottom of the foundation pile is 10.

[0037] The welding of the reinforcing bars is explained as follows: (1) The horizontal reinforcing bars are welded at certain intervals to connect the steel casing 4 into a whole, which can play a supporting role for the well wall and prevent the soil from falling off the well wall. (2) The spacing formed by the upper and lower welding of the horizontal reinforcing bars can be used to drill and measure the pile diameter of the foundation pile; to use a rebound hammer to test the pile body strength; and to test the position and range of the diameter reduction. (3) The vertical reinforcing bars are used to connect the upper and lower casings 4, so that the individual casings 4 are connected to each other to form a whole, which can play a supporting role. (4) When the steel casing 4 is hoisted, it is hoisted downward from the well opening. First, the casings 4 are put together and sent to the support position. Then the steel casing 4 is opened and the reinforcing bars are welded horizontally and vertically to form an integral steel casing 4 support structure.

[0038] The soil hoisting device 2 is set at the opening excavated on the side of the existing building foundation pile 5, and the soil transfer device 1 is installed at the ground opening. The soil generated during the excavation process is transported out of the opening through the soil hoisting device 2 and the soil transfer device 1 and discharged to the ground.

[0039] Step Six: Confirm the position of pile bottom 10: In step 601, when the exploratory well is excavated to the elevation of the bottom 10th section of the foundation pile, it is necessary to excavate downwards by about 30cm and then radially over-excavate about 10cm to the inside of the bottom 10th section of the foundation pile.

[0040] Step 602: At the elevation position of the bottom 10 of the foundation pile, drive a steel bar slightly longer than the diameter of the foundation pile radially along the horizontal direction, close to the bottom 10 of the foundation pile, to confirm that the depth of the exploratory well has reached the actual construction depth of the foundation pile.

[0041] Step 7: Inspection of pile length, pile verticality, and reinforcement cage length: Step 701 involves using magnetic measurement to detect the length of the reinforcing cage.

[0042] Step 702 involves measuring the length of the foundation piles using a direct measurement method.

[0043] Step 703 uses a verticality measuring instrument to measure the verticality of the foundation piles.

[0044] In summary, this invention is reasonably designed and easy to operate, and can accurately detect the integrity of the pile body, the quality of the concrete, the condition of the reinforcing steel, and the verticality of the pile, thereby providing a basis for the subsequent foundation reinforcement construction of existing buildings.

[0045] The sequence numbers of the embodiments in this application are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0046] In the above embodiments of this application, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0047] In the several embodiments provided in this application, it should be understood that the disclosed technical content can be implemented in other ways. The device embodiments described above are merely illustrative; for example, the division of units can be a logical functional division, and in actual implementation, there may be other division methods. For instance, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the displayed or discussed mutual coupling, direct coupling, or communication connection may be through some interfaces; the indirect coupling or communication connection between units or modules may be electrical or other forms.

[0048] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0049] The above description is only a preferred embodiment of this application. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of this application, and these improvements and modifications should also be considered within the scope of protection of this application.

[0050] It should be understood that the above description is for illustrative purposes and not for limitation. Many embodiments and applications beyond the provided examples will be apparent to those skilled in the art upon reading the above description. Therefore, the scope of this patent should not be determined by reference to the above description, but rather by reference to the foregoing claims and the full scope of their equivalents. For purposes of completeness, all articles and references, including patent applications and publications, are incorporated herein by reference. The omission of any aspect of the subject matter disclosed herein in the foregoing claims is not intended as a waiver of that subject matter, nor should it be construed as an indication that the applicant has not considered that subject matter as part of the disclosed inventive subject matter.

Claims

1. A method for testing the quality of foundation piles in existing buildings, characterized in that, Includes the following processes: Excavate a trench along one side of the pile cap (6) to expose the bottom of the pile cap (6), and excavate towards the inside of the pile cap (6) to expose the existing building piles (5), forming a soil transfer platform (3). Excavate a test well downwards from the soil transfer platform (3) along one side of the existing building foundation piles (5); After each exploration well is excavated to a predetermined depth, an unclosed casing (4) is installed for support, with the unclosed opening of the unclosed casing (4) facing the existing building foundation piles (5). The quality of the pile body is inspected through the unsealed opening of the non-enclosed casing (4); Repeat the steps of installing the non-enclosed casing (4) and performing quality inspection until the bottom of the pile (10) is reached. Confirm the position of the pile bottom (10); Inspect the pile length, pile verticality, and reinforcement cage length.

2. The method for testing the quality of existing building foundation piles according to claim 1, characterized in that, Before excavating the trench, ground-penetrating radar is used to conduct a preliminary survey of the area to be excavated in order to identify the underground pipelines buried in the area.

3. The method for testing the quality of existing building foundation piles according to claim 1, characterized in that, The soil generated during the excavation of the exploratory well is transported out and discharged to the ground through the soil hoisting device (2) set at the wellhead and the soil transfer device (1) set at the trench opening.

4. The method for testing the quality of existing building foundation piles according to claim 1, characterized in that, The steps for installing non-enclosed casing (4) for support are carried out using the reverse construction method.

5. The method for testing the quality of existing building foundation piles according to claim 1, characterized in that, The upper and lower adjacent non-enclosed casings (4) are connected by welding a vertical steel bar; each non-enclosed casing (4) is welded with a horizontal steel bar at intervals.

6. The method for testing the quality of existing building foundation piles according to claim 1, characterized in that, The steps for quality inspection of the pile body include: using a rebound hammer to test the concrete strength of the pile body; using the core drilling method to drill through the existing building foundation pile (5) and test the pile diameter.

7. The method for testing the quality of existing building foundation piles according to claim 6, characterized in that, The steps for quality inspection of the pile body also include: when encountering a broken pile (9), detecting the location, crack length and crack depth of the broken pile (9); when encountering a local reduction in diameter of the pile body (7), detecting the location and range of the local reduction in diameter (7).

8. The method for testing the quality of existing building foundation piles according to claim 6, characterized in that, The steps for quality inspection of the pile body also include: when encountering a local enlargement of the pile diameter (8), a static expansion agent is embedded to break up the part of the local enlargement of the pile diameter (8).

9. The method for testing the quality of existing building foundation piles according to claim 1, characterized in that, The steps to confirm the location of the pile bottom (10) include: excavating downward at an elevation position of the pile bottom (10) and over-excavating radially towards the inside of the pile bottom (10); driving a steel bar longer than the diameter of the foundation pile (5) into the pile bottom (10) along a horizontal direction below the elevation position of the pile bottom (10).

10. The method for testing the quality of existing building foundation piles according to claim 1, characterized in that, The steps for detecting pile length, pile verticality, and reinforcement cage length include: using magnetic measurement to detect the reinforcement cage length; using direct measurement to measure the pile length; and using a verticality meter to measure the pile verticality.

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