Construction method for steep slope section large-diameter pressure steel pipe support

Abstract

The invention relates to the technical field of pipeline engineering, in particular to a steep slope section large-diameter pressure steel pipe support construction method which comprises the following steps: acquiring a foundation bearing capacity characterization value through field survey and determining the mounting position of a pressure steel pipe; temporary supports are installed at the preset point positions, and the distance between buttresses is determined according to the characterization value of the foundation bearing capacity; first-stage concrete of the buttress is poured and cured; pre-embedded steel bars are installed on the first-stage concrete base face of the buttress, and the U-shaped bars of the pre-embedded steel plate and the pre-embedded steel bars of the buttress are welded and fixed; a sliding support is installed on the upper surface of the embedded steel plate; the pressure steel pipe supporting ring is connected with a supporting leg of the sliding support through a bolt; second-stage concrete formworks are installed on the vertical faces of the two sides, parallel to the axis of the pressure steel pipe, of the buttress; and second-stage concrete of the buttress is poured and cured. According to the invention, the construction precision is improved.

Description

Technical Field

[0001] This invention relates to the field of pipeline engineering technology, and in particular to a construction method for a large-diameter pressure steel pipe support on a steep slope. Background Technology

[0002] In water conservancy and hydropower engineering construction, pressure steel pipes are crucial channels for water transportation. Especially in steep slope sections, the installation and support construction of pressure steel pipes face numerous challenges. Steep terrain increases the difficulty of positioning and installing pressure steel pipes, and traditional construction methods struggle to guarantee accurate positioning and stable support in complex terrain. Furthermore, the large-diameter pressure steel pipes themselves are heavy and subject to complex stresses, placing higher demands on the strength, stability, and adaptability of the supports.

[0003] Existing support construction methods for large-diameter pressure steel pipes on steep slopes suffer from problems such as inaccurate positioning, unstable connection between the support and the steel pipe, and susceptibility to interference from terrain and external factors during construction. These issues can lead to displacement, deformation, or even damage of the pressure steel pipe during operation, affecting the safety and normal operation of the entire water conservancy project. Therefore, developing a construction method suitable for large-diameter pressure steel pipe supports on steep slopes is of significant practical importance.

[0004] Chinese Patent Publication No. CN114704688B discloses a construction method for a pressure steel pipe in a large-span inverted siphon slope section. The construction method includes the following steps: S1, construction preparation; S2, hoisting of the initial section; S3, installation of the winch; S4, installation of pipe sections; S5, installation of pressure steel pipe supports and hangers; S6, installation of the initial section; S7, installation of the remaining pipe sections; S8, removal of temporary fixtures and repair of pipe wall defects.

[0005] However, the existing technology has the following problems: when dealing with large-diameter pressure steel pipes on steep slopes, the existing support construction methods have problems such as inaccurate positioning, unstable connection between the support and the steel pipe, and the construction process is easily affected by terrain and external factors. As a result, the pressure steel pipe may be displaced, deformed or even damaged during operation, which affects the safety and normal operation of the entire water conservancy project. Summary of the Invention

[0006] Therefore, the present invention provides a construction method for large-diameter pressure steel pipe supports on steep slopes, in order to overcome the problems of inaccurate positioning and unstable connection of pressure steel pipe supports during construction in the prior art.

[0007] To achieve the above objectives, the present invention provides a construction method for large-diameter pressure steel pipe supports on steep slopes, comprising:

[0008] Step S1: Obtain the bearing capacity characterization value of the foundation through on-site survey and determine the installation location of the pressure steel pipe;

[0009] Step S2: Install temporary supports at preset locations and determine the spacing of the supports based on the bearing capacity characterization value of the foundation.

[0010] Step S3: Pour the first phase of concrete for the support pier and cure it;

[0011] Step S4: Install pre-embedded steel bars on the first-stage concrete base of the support pier, and weld and fix the U-shaped bars of the pre-embedded steel plate to the pre-embedded steel bars of the support pier.

[0012] Step S5: Install sliding supports on the upper surface of the pre-embedded steel plate;

[0013] Step S6: Connect the pressure steel pipe to the support leg of the sliding support using bolts;

[0014] Step S7: Install the second-stage concrete formwork on the two sides of the support pier parallel to the axis of the pressure steel pipe.

[0015] Step S8: Pour the second phase of concrete for the support pier and cure it.

[0016] Furthermore, the bearing capacity characterization value of the foundation is determined by the soil shear strength index and the soil deformation modulus.

[0017] Furthermore, the spacing of the piers is determined based on the characteristic value of the foundation bearing capacity, wherein,

[0018] If the characteristic value of the foundation bearing capacity is less than the first preset bearing capacity threshold, then the spacing of the supports is determined to be the first preset spacing.

[0019] If the characteristic value of the foundation bearing capacity is greater than or equal to the first preset bearing capacity threshold and less than the second preset bearing capacity threshold, then the spacing of the piers is determined to be the second preset spacing.

[0020] If the characteristic value of the foundation bearing capacity is greater than or equal to the second preset bearing capacity threshold, then the spacing of the piers is determined to be the third preset spacing.

[0021] Furthermore, the temporary support is an adjustable jack, with a set arranged at preset intervals along the axis of the pressure steel pipe.

[0022] Furthermore, the first-stage concrete pouring process in step S3 includes:

[0023] S301, Erect formwork and tie reinforcement according to the designed pier dimensions;

[0024] S302, pour the first phase of concrete, control the top surface elevation of the concrete, and expose the pre-embedded anchor bars for the preset length;

[0025] S303: Remove the formwork after the concrete has cured to the preset strength.

[0026] Furthermore, the welding of the U-shaped rib to the embedded steel plate adopts a double-sided continuous fillet weld.

[0027] Furthermore, the installation process of the sliding support in step S5 includes:

[0028] S501 uses a total station to control the flatness deviation of the sliding support installation to be less than the preset deviation;

[0029] S502 uses spot welding to temporarily fix the support.

[0030] Furthermore, the second-stage concrete pouring process in step S8 includes:

[0031] S801 uses micro-expansion concrete poured in layers, with each layer having a thickness less than or equal to the second preset thickness.

[0032] S802 uses an immersion vibrator for compaction, with the compaction spacing being less than or equal to the preset spacing.

[0033] S803, after pouring, cover with geotextile and maintain moisture for the preset number of days.

[0034] Compared with existing technologies, the advantages of this invention lie in its determination of the installation position of the pressure steel pipe by obtaining the bearing capacity characterization value of the foundation through on-site surveying. This precise positioning method based on actual foundation conditions avoids the positioning deviations caused by insufficient estimation of foundation conditions or inaccurate measurements in traditional methods. Simultaneously, during the installation of the sliding bearing, a total station is used to strictly control the installation flatness deviation to be less than the preset deviation, further ensuring the accuracy of the bearing installation position. This provides a reliable foundation for the stable installation and subsequent operation of the pressure steel pipe, effectively solving the problem of inaccurate positioning of pressure steel pipe bearings in existing technologies.

[0035] Furthermore, in the connection between the support pier and the embedded steel plate, the U-shaped reinforcement of the embedded steel plate is welded and fixed to the embedded steel reinforcement of the support pier using double-sided continuous fillet welds. This welding method enhances the strength and reliability of the connection, effectively preventing support displacement or damage caused by loosening of the connection. Regarding the connection between the pressure steel pipe and the sliding support, bolted connections ensure a tight bond between the two, enabling them to withstand various stresses generated by the pressure steel pipe during operation and guaranteeing connection stability. In addition, the support pier spacing is rationally determined based on the characteristic value of the foundation bearing capacity, allowing the entire support structure to better adapt to foundation conditions, further improving connection stability and overcoming the defects of unstable connections in existing technologies.

[0036] Furthermore, this invention, through clearly defining the requirements for setting up formwork and tying reinforcing bars according to the designed pier dimensions during the first-phase concrete pouring process, ensuring the pre-embedded anchor bars are exposed to a predetermined length during pouring, and removing the formwork after the concrete has cured to a predetermined strength, ensures the quality of the first-phase concrete construction. During the second-phase concrete pouring, micro-expansion concrete is poured in layers, with each layer less than or equal to the second predetermined thickness. Simultaneously, an immersion vibrator is used for compaction, controlling the vibration spacing to be less than or equal to the predetermined spacing. After pouring, geotextile is covered for moisture retention and curing for a predetermined number of days. These measures effectively guarantee the compactness and strength of the second-phase concrete, reduce the occurrence of quality problems such as concrete cracks, and thus improve the overall construction quality of the large-diameter pressure steel pipe supports on the steep slope section. Attached Figure Description

[0037] Fig. 1 This is a flowchart illustrating the construction method of large-diameter pressure steel pipe supports on steep slopes according to an embodiment of the present invention.

[0038] Fig. 2 This is a flowchart of the concrete pouring process in the first phase of an embodiment of the present invention;

[0039] Fig. 3 This is a flowchart illustrating the installation process of the sliding support according to an embodiment of the present invention;

[0040] Fig. 4 This is a flowchart of the concrete pouring process in the second phase of an embodiment of the present invention. Detailed Implementation

[0041] To make the objectives and advantages of the present invention clearer, the present invention will be further described below with reference to embodiments; it should be understood that the specific embodiments described herein are merely for explaining the present invention and are not intended to limit the present invention.

[0042] Preferred embodiments of the present invention will now be described with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are merely illustrative of the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0043] It should be noted that the data in this embodiment are all derived from a comprehensive analysis and evaluation of historical test data and corresponding historical test results from the three months prior to this test. Those skilled in the art will understand that the determination of the above-mentioned parameters for any single item in this invention can be achieved by selecting the value with the highest percentage based on the data distribution as the preset standard parameter, using weighted summation to obtain the value as the preset standard parameter, substituting each historical data point into a specific formula and using the value obtained from that formula as the preset standard parameter, or other selection methods, as long as the invention can clearly define different specific situations in the single-item judgment process through the obtained values.

[0044] Please see Figs. 1 to 4 As shown, these are flowcharts of the construction method of large-diameter pressure steel pipe support on steep slope section according to an embodiment of the present invention; flowchart of the first-stage concrete pouring process according to an embodiment of the present invention; flowchart of the installation process of sliding support according to an embodiment of the present invention; and flowchart of the second-stage concrete pouring process according to an embodiment of the present invention.

[0045] The present invention provides a method for constructing large-diameter pressure steel pipe supports on steep slopes, comprising:

[0046] Step S1: Obtain the bearing capacity characterization value of the foundation through on-site survey and determine the installation location of the pressure steel pipe;

[0047] Step S2: Install temporary supports at preset locations and determine the spacing of the supports based on the bearing capacity characterization value of the foundation.

[0048] Step S3: Pour the first phase of concrete for the support pier and cure it;

[0049] Step S4: Install pre-embedded steel bars on the first-stage concrete base of the support pier, and weld and fix the U-shaped bars of the pre-embedded steel plate to the pre-embedded steel bars of the support pier.

[0050] Step S5: Install sliding supports on the upper surface of the pre-embedded steel plate;

[0051] Step S6: Connect the pressure steel pipe to the support leg of the sliding support using bolts;

[0052] Step S7: Install the second-stage concrete formwork on the two sides of the support pier parallel to the axis of the pressure steel pipe.

[0053] Step S8: Pour the second phase of concrete for the support pier and cure it.

[0054] Specifically, the on-site survey uses a total station for precise measurement and positioning to ensure that the axial position, elevation and slope of the pressure steel pipe meet the design requirements. The cohesion and internal friction angle of the soil are obtained through direct shear test. The effective normal stress is measured by burying earth pressure cells in the foundation of the proposed building. The deformation modulus of the soil is obtained through plate load test.

[0055] Specifically, the bearing capacity characterization value is determined by the soil shear strength index and the soil deformation modulus. The bearing capacity characterization value = first weighting coefficient × soil shear strength index / shear strength index threshold + second weighting coefficient × soil deformation modulus / deformation modulus threshold. The first weighting coefficient is 0.6, the soil shear strength index = cohesion + effective normal stress × tangent of internal friction angle, the shear strength index threshold is 120 kPa, the second weighting coefficient is 0.4, and the deformation modulus threshold is 50 MPa. However, the above values ​​are not limited to these values, and those skilled in the art can adjust the above values ​​according to actual needs.

[0056] Specifically, the spacing of the piers is determined based on the characteristic value of the foundation bearing capacity, wherein,

[0057] If the characteristic value of the foundation bearing capacity is less than the first preset bearing capacity threshold, then the spacing of the supports is determined to be the first preset spacing.

[0058] If the characteristic value of the foundation bearing capacity is greater than or equal to the first preset bearing capacity threshold and less than the second preset bearing capacity threshold, then the spacing of the piers is determined to be the second preset spacing.

[0059] If the characteristic value of the foundation bearing capacity is greater than or equal to the second preset bearing capacity threshold, then the spacing of the piers is determined to be the third preset spacing.

[0060] In this embodiment of the invention, the first preset bearing capacity threshold is 0.8, the second preset bearing capacity threshold is 0.9, the first preset spacing is 6m, the second preset spacing is 8m, and the third preset spacing is 10m. However, the above values ​​are not limited to these values, and those skilled in the art can adjust the above values ​​according to actual needs.

[0061] Specifically, the temporary support is an adjustable jack, with a set arranged at preset intervals along the axis of the pressure steel pipe.

[0062] In this embodiment of the invention, the preset distance range is 3 to 7m, and there is no specific limitation. It needs to be adjusted according to the actual slope of the steep slope. When the slope is less than or equal to 20°, the distance is set to 7m. When the slope is greater than 20°, the distance is reduced by 15% to 20% for every 10° increase in slope.

[0063] Specifically, the first-stage concrete pouring process in step S3 includes:

[0064] S301, Erect formwork and tie reinforcement according to the designed pier dimensions;

[0065] S302, pour the first phase of concrete, control the top surface elevation of the concrete, and expose the pre-embedded anchor bars for the preset length;

[0066] S303: Remove the formwork after the concrete has cured to the preset strength.

[0067] In this embodiment of the invention, the tied reinforcing bars include pre-embedded anchor bars with a preset length of 300mm and a preset strength of 25MPa. However, the above values ​​are not limited to these values, and those skilled in the art can adjust the above values ​​according to actual needs.

[0068] Specifically, the welding of the U-shaped rib to the embedded steel plate adopts a double-sided continuous fillet weld.

[0069] Specifically, the installation process of the sliding support in step S5 includes:

[0070] S501 uses a total station to control the flatness deviation of the sliding support installation to be less than the preset deviation;

[0071] S502 uses spot welding to temporarily fix the support.

[0072] In this embodiment of the invention, the preset deviation value is 1 mm / m, but the above value is not limited to this. Those skilled in the art can adjust the above value according to actual needs.

[0073] Specifically, the second-stage concrete pouring process in step S8 includes:

[0074] S801 uses micro-expansion concrete poured in layers, with each layer having a thickness less than or equal to the second preset thickness.

[0075] S802 uses an immersion vibrator for compaction, with the compaction spacing being less than or equal to the preset spacing.

[0076] S803, after pouring, cover with geotextile and maintain moisture for the preset number of days.

[0077] In this embodiment of the invention, the second preset thickness is 40cm, the preset spacing is 60cm, and the preset number of days is 14 days. However, the above values ​​are not limited to these, and those skilled in the art can adjust the above values ​​according to actual needs.

[0078] The technical solution of the present invention has been described above with reference to the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the scope of protection of the present invention.

[0079] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A construction method for large-diameter pressure steel pipe supports on steep slopes, characterized in that, include: Step S1: Obtain the bearing capacity characterization value of the foundation through on-site survey and determine the installation location of the pressure steel pipe; Step S2: Install temporary supports at preset locations and determine the spacing of the supports based on the bearing capacity characterization value of the foundation. Step S3: Pour the first phase of concrete for the support pier and cure it; Step S4: Install pre-embedded steel bars on the first-stage concrete base of the support pier, and weld and fix the U-shaped bars of the pre-embedded steel plate to the pre-embedded steel bars of the support pier. Step S5: Install sliding supports on the upper surface of the pre-embedded steel plate; Step S6: Connect the pressure steel pipe to the support leg of the sliding support using bolts; Step S7: Install the second-stage concrete formwork on the two sides of the support pier parallel to the axis of the pressure steel pipe. Step S8: Pour the second phase of concrete for the support pier and cure it.

2. The construction method for large-diameter pressure steel pipe supports on steep slopes according to claim 1, characterized in that, The bearing capacity of the foundation is determined by the soil shear strength index and the soil deformation modulus.

3. The construction method for large-diameter pressure steel pipe supports on steep slopes according to claim 2, characterized in that, The spacing of the piers is determined based on the characteristic value of the foundation bearing capacity, wherein, If the characteristic value of the foundation bearing capacity is less than the first preset bearing capacity threshold, then the spacing of the supports is determined to be the first preset spacing. If the characteristic value of the foundation bearing capacity is greater than or equal to the first preset bearing capacity threshold and less than the second preset bearing capacity threshold, then the spacing of the piers is determined to be the second preset spacing. If the characteristic value of the foundation bearing capacity is greater than or equal to the second preset bearing capacity threshold, then the spacing of the piers is determined to be the third preset spacing.

4. The construction method for large-diameter pressure steel pipe supports on steep slopes according to claim 3, characterized in that, The temporary support consists of adjustable jacks, arranged at preset intervals along the axis of the pressure steel pipe.

5. The construction method for large-diameter pressure steel pipe supports on steep slopes according to claim 4, characterized in that, The process of pouring the first-stage concrete in step S3 includes: S301, Erect formwork and tie reinforcement according to the designed pier dimensions; S302, pour the first phase of concrete, control the top surface elevation of the concrete, and expose the pre-embedded anchor bars by the preset length. S303: Remove the formwork after the concrete has cured to the preset strength.

6. The construction method for large-diameter pressure steel pipe supports on steep slopes according to claim 5, characterized in that, The U-shaped ribs are welded to the embedded steel plates using double-sided continuous fillet welds.

7. The construction method for large-diameter pressure steel pipe supports on steep slopes according to claim 6, characterized in that, The installation process of the sliding support in step S5 includes: S501 uses a total station to control the flatness deviation of the sliding support installation to be less than the preset deviation; S502 uses spot welding to temporarily fix the support.

8. The construction method for large-diameter pressure steel pipe supports on steep slopes according to claim 7, characterized in that, The second-stage concrete pouring process in step S8 includes: S801 uses micro-expansion concrete poured in layers, with each layer having a thickness less than or equal to the second preset thickness. S802 uses an immersion vibrator for compaction, with the compaction spacing being less than or equal to the preset spacing. S803, after pouring, cover with geotextile and maintain moisture for the preset number of days.

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