A method for constructing a steel pipe pile cofferdam with a low pile cap on a ridge-shaped riverbed

Abstract

The present invention relates to the technical field of steel trestles on water, and in particular to a method for constructing a steel pipe pile cofferdam with a low pile foundation on a ridge-shaped riverbed surface. The method comprises the following steps: obtaining data of a ridge-shaped riverbed surface on a construction site; determining a type of a construction area based on comprehensive characterization parameters; determining whether the first steel pipe pile has an impact on the driving process of remaining steel pipe piles based on an influence characterization value of the first steel pipe pile; reducing the vibration frequency of a vibrating hammer based on a difference between the influence characterization value and a preset influence characterization value; determining whether the driving of a whole row of steel pipe piles is qualified based on an overall uniformity evaluation value of the whole row of steel pipe piles; increasing the driving spacing of steel pipe piles based on a ratio of the overall uniformity evaluation value to an overall uniformity evaluation threshold; inserting a steel pipe pile at the center of the cofferdam, and determining the eligibility of the cofferdam installation based on an offset distance of the cofferdam after vibration; and determining a reduction in the influence range based on a relative difference between the offset distance and the preset offset distance. The present invention improves the efficiency of cofferdam construction.

Description

Technical Field

[0001] The invention relates to the technical field of steel trestle bridges on water, in particular to a method for constructing a steel pipe pile cofferdam with a low pile cap on a ridge-shaped riverbed surface. Background Art

[0002] Due to the undulating terrain and complex water flow in ridge-shaped riverbeds, traditional cofferdam construction methods are difficult to adapt to the dynamic changes in geological and hydrological conditions. With the increasing demand for overwater steel trestle projects, low-pile cap steel pipe pile cofferdam technology has become increasingly important. Steel pipe pile cofferdam technology is a relatively advanced cofferdam method suitable for deepwater foundation construction. It offers advantages such as fast construction, good stability, and strong adaptability.

[0003] Chinese patent application publication number: CN111456049A discloses a construction method for a steel sheet pile cofferdam with a low pile foundation in an uncovered water area, comprising the following steps: cleaning the riverbed surface at the design location of the steel sheet pile cofferdam; setting a guide device at a corresponding position on the water surface according to the design location, and welding the guide device to a bracket of a steel pipe pile; without milling a groove in the rock layer at the design location, driving the steel sheet piles along the outer wall direction of the guide device to the design location, and connecting them end to end to form a steel sheet pile cofferdam; lowering the bottom layer internal support into the steel sheet pile cofferdam and welding and fixing them to the steel sheet pile cofferdam via tie rods; lowering the middle layer internal support and the top layer internal support into the steel sheet pile cofferdam in turn and fixing them; and performing high-pressure grouting on the rock layer in the steel sheet pile cofferdam using grouting equipment to make the rock layer in the steel sheet pile cofferdam impermeable.

[0004] However, the existing technology has the following problems: the existing technology is based on homogeneous riverbed design and lacks targeted analysis of irregular riverbeds, especially ridge-shaped riverbed surfaces, which leads to low cofferdam construction efficiency. Summary of the Invention

[0005] To this end, the present invention provides a method for constructing a cofferdam with low pile caps and steel pipe piles on a ridge-shaped riverbed surface, so as to overcome the problem in the prior art of lack of targeted analysis of irregular riverbeds, especially ridge-shaped riverbed surfaces, which leads to low cofferdam construction efficiency.

[0006] To achieve the above object, the present invention provides a method for constructing a steel pipe pile cofferdam with a low pile cap on a ridge-shaped riverbed, comprising:

[0007] Obtain geological and hydrological data of the ridge-shaped riverbed surface at the construction site;

[0008] Determine whether the construction area is a stable zone or a scour zone based on the comprehensive characterization parameters of the ridge-shaped riverbed surface at the construction site;

[0009] The influence characterization value of the first steel pipe pile driven by the vibratory hammer is used to determine whether the first steel pipe pile has an impact on the driving process of the remaining steel pipe piles;

[0010] Under the condition that it is determined that the first steel pipe pile has an impact on the driving process of the remaining steel pipe piles, the vibration frequency of the vibratory hammer is reduced based on the difference between the impact effect characterization value and the preset impact effect characterization value;

[0011] Determine whether the entire row of steel pipe piles is qualified based on the overall uniformity evaluation value of the entire row of steel pipe piles;

[0012] Under the condition that the entire row of steel pipe piles is determined to be unqualified, the driving spacing of the steel pipe piles is increased based on the ratio of the overall uniformity evaluation value to the overall uniformity evaluation threshold;

[0013] After all the steel pipe piles are driven, the purlins and inner supports are installed inside the steel pipe piles to complete the cofferdam installation. A steel pipe pile is inserted in the center of the cofferdam. The eligibility of the cofferdam installation is determined based on the offset distance of the cofferdam after vibration.

[0014] Under the condition that the cofferdam installation is determined to be unqualified, the impact range is reduced based on the relative difference between the offset distance and the preset offset distance;

[0015] Pump water out of the cofferdam, tie the pedestal reinforcement, install the pedestal formwork, and pour the pedestal concrete.

[0016] Furthermore, based on the comparison result that the comprehensive characterization parameters of the ridge-shaped riverbed surface are less than or equal to the preset comprehensive characterization parameters, the construction area is determined to be a stable area, and the diameter of the steel pipe piles is determined to be 60cm-70cm, and the driving spacing of the steel pipe piles is determined to be 1.5m.

[0017] Furthermore, based on the comparison result that the comprehensive characterization parameters of the ridge-shaped riverbed surface are greater than the preset comprehensive characterization parameters, the construction area is determined to be an erosion area, and the diameter of the steel pipe piles is determined to be 90cm-100cm, and the spacing between the steel pipe piles is determined to be 1.0m.

[0018] Furthermore, under the condition of determining the type of construction area, based on the comparison result that the influence characterization value of the first steel pipe pile after driving is greater than the preset influence characterization value, it is determined that the first steel pipe pile has an impact on the driving process of the remaining steel pipe piles.

[0019] Furthermore, based on the deformation value of a single steel pipe pile on the ridge-shaped riverbed surface after the steel pipe pile is driven, it is determined that the influence range of the first steel pipe pile is 2 times the diameter range of the steel pipe pile.

[0020] Furthermore, based on the comparison result of the difference between the impact characterization value and the preset impact characterization value and the preset difference, it is determined that the vibration frequency of the vibration hammer is reduced by the first preset frequency adjustment coefficient or the second preset frequency adjustment coefficient.

[0021] Furthermore, under the condition of adjusting the vibration frequency of the vibratory hammer, the entire row of steel pipe piles is driven into the ridge-shaped riverbed surface, and based on the comparison result that the overall uniformity evaluation value of the entire row of steel pipe piles is less than the overall uniformity evaluation threshold, it is determined that the entire row of steel pipe piles has failed the driving.

[0022] Furthermore, based on the deformation values ​​of the entire row of ridge-shaped riverbed surfaces after the steel pipe piles are driven, it is determined that the influence range of the entire row of steel pipe piles is 5 times the diameter range of the steel pipe piles.

[0023] Furthermore, under the condition that it is determined that the driving of an entire row of steel pipe piles is unqualified, based on the comparison result of the ratio of the overall uniformity evaluation value to the overall uniformity evaluation threshold and the preset ratio, it is determined to increase the driving spacing of the steel pipe piles by the first preset spacing adjustment coefficient or the second preset spacing adjustment coefficient.

[0024] Furthermore, based on the comparison result that the offset distance of the cofferdam after vibration is greater than the preset offset distance, it is determined that the cofferdam installation is unqualified, and based on the comparison result of the relative difference between the offset distance and the preset offset distance and the preset relative difference, it is determined that the influence range is reduced by the first preset influence range adjustment coefficient or the second preset influence range adjustment coefficient.

[0025] Compared with the existing technology, the beneficial effect of the present invention is that the present invention judges the stability of the construction area, adjusts the subsequent driving strategy according to the influence of the first steel pipe pile, ensures the uniformity and stability of the entire row of steel pipe piles, verifies the cofferdam installation, reduces the impact range, ensures the stability of the cofferdam, and thus improves the cofferdam construction efficiency.

[0026] Furthermore, the present invention determines the type of construction area through the comprehensive characterization parameters of the ridge-shaped riverbed surface, adjusts the size and driving spacing of the steel pipe piles, compares the impact characterization value after the driving of the first steel pipe pile to judge the impact on the subsequent driving process, thereby improving the safety of construction, monitoring the impact of the driving of the first steel pipe pile in real time, adjusting the subsequent construction strategy, ensuring the stability and uniformity of the entire row of steel pipe piles, and thus improving the cofferdam construction efficiency.

[0027] Furthermore, the present invention determines the impact of the driving of the first steel pipe pile, determines the impact range based on the deformation value of a single pile, and adjusts the frequency of the vibrating hammer, thereby achieving precise control of the impact of the driving of the steel pipe piles. By adjusting the frequency of the vibrating hammer, the interference with the subsequent driving process of the steel pipe piles is reduced, thereby ensuring the stability of the overall construction.

[0028] Furthermore, the present invention determines whether the steel pipe piles are qualified by calculating the overall uniformity evaluation value of the entire row of steel pipe piles. If they are unqualified, the driving spacing of the steel pipe piles is adjusted to ensure the driving quality of the steel pipe piles on the ridge-shaped riverbed surface. By adjusting the driving spacing, the overall stability is optimized and the riverbed deformation is reduced.

[0029] Furthermore, the present invention determines the eligibility of the cofferdam installation by vibrating the steel pipe piles and comparing the offset distances, and adjusts the impact range for unqualified cases, thereby ensuring the accuracy of the cofferdam installation and improving the construction efficiency and quality by adjusting the impact range. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 Flowchart of a method for constructing a steel pipe pile cofferdam with a low pile cap on a ridge-shaped riverbed according to an embodiment of the present invention;

[0031] Figure 2 A flowchart for determining the type of a construction area according to an embodiment of the present invention;

[0032] Figure 3 A flow chart showing the qualification of an entire row of steel pipe piles according to an embodiment of the present invention;

[0033] Figure 4 A flow chart for determining the eligibility of cofferdam installation according to an embodiment of the present invention. DETAILED DESCRIPTION

[0034] In order to make the objects and advantages of the present invention more clearly understood, the present invention is further described below in conjunction with embodiments; it should be understood that the specific embodiments described herein are merely used to explain the present invention and are not intended to limit the present invention.

[0035] The preferred embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood by those skilled in the art that these embodiments are only used to explain the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0036] It should be pointed out that the data in this embodiment are obtained by comprehensive analysis and evaluation of the historical test data and the corresponding historical test results of the three months before this test. It can be understood by those skilled in the art that the present invention can determine the above parameters for a single item by selecting the value with the highest proportion as the preset standard parameter based on the data distribution, using weighted summation to use the obtained value as the preset standard parameter, substituting each historical data into a specific formula and using the value obtained by the formula as the preset standard parameter or other selection methods, as long as the present invention can clearly define the different specific situations in the single determination process through the obtained values.

[0037] See also Figure 1 The flow chart of the steel pipe pile cofferdam construction method based on the low pile cap on the ridge-shaped riverbed is shown in the figure.

[0038] The embodiment of the present invention is based on a method for constructing a steel pipe pile cofferdam with a low pile cap on a ridge-shaped riverbed, comprising:

[0039] Step S1, obtaining geological data and hydrological data of the ridge-shaped riverbed surface at the construction site;

[0040] Step S2: determining whether the construction area is a stable area or a scouring area based on comprehensive characterization parameters of the ridge-shaped riverbed surface at the construction site;

[0041] Step S3, determining whether the first steel pipe pile has an impact on the driving process of the remaining steel pipe piles through the influence characterization value of the first steel pipe pile driven by the vibrating hammer;

[0042] Step S4, under the condition that it is determined that the first steel pipe pile will affect the driving process of the remaining steel pipe piles, determining to reduce the vibration frequency of the vibratory hammer based on the difference between the influence effect characterization value and the preset influence effect characterization value;

[0043] Step S5, determining whether the entire row of steel pipe piles is qualified based on the overall uniformity evaluation value of the entire row of steel pipe piles;

[0044] Step S6, when it is determined that the entire row of steel pipe piles is unqualified, determining to increase the driving spacing of the steel pipe piles based on the ratio of the overall uniformity evaluation value to the overall uniformity evaluation threshold;

[0045] Step S7: After all steel pipe piles are driven, purlins and inner supports are installed inside the steel pipe piles to complete the cofferdam installation. A steel pipe pile is inserted into the center of the cofferdam, and the eligibility of the cofferdam installation is determined based on the offset distance of the cofferdam after vibration.

[0046] Step S8, if it is determined that the cofferdam installation is unqualified, determining a reduction range of influence based on a relative difference between the offset distance and a preset offset distance;

[0047] Step S9: pump water out of the cofferdam, tie the cap steel bars after pumping out, install the cap formwork, and pour the cap concrete.

[0048] In the embodiment of the present invention, the geological data is the height difference and slope of the ridge-shaped riverbed surface, the hydrological data is the flow velocity of the water flow, and the height difference is the vertical height difference of the riverbed.

[0049] In the embodiment of the present invention, the geological data is measured by a total station, and the hydrological data is measured by a current meter. There is no specific limitation, as long as the geological data and the hydrological data can be measured.

[0050] In the embodiment of the present invention, the vibratory hammer is a hydraulic vibratory hammer, and the vibratory hammer drives the steel pipe pile at a vibration frequency of 35 Hz.

[0051] Specifically, the present invention judges the stability of the construction area and adjusts the subsequent driving strategy according to the impact of the first steel pipe pile, thereby ensuring the uniformity and stability of the entire row of steel pipe piles, verifying the cofferdam installation, reducing the impact range, ensuring the stability of the cofferdam, and thus improving the cofferdam construction efficiency.

[0052] See also Figure 2 The flow chart for determining the type of construction area is shown below.

[0053] Specifically, the embodiment of the present invention determines the type of the construction area based on the comparison result of the comprehensive characterization parameter of the ridge-shaped riverbed surface of the construction site and the preset comprehensive characterization parameter 0.80;

[0054] When the comprehensive characterization parameter is less than or equal to the preset comprehensive characterization parameter, the construction area is determined to be a stable area, and the diameter of the steel pipe pile is determined to be 60 cm-70 cm, preferably 65 cm, and the driving spacing of the steel pipe pile is 1.5 m;

[0055] When the comprehensive characterization parameter is greater than the preset comprehensive characterization parameter, the construction area is determined to be a scour area, and the size of the steel pipe pile is determined to be 90cm-100cm, preferably 95cm, and the steel pipe pile driving spacing is 1.0m.

[0056] In the embodiment of the present invention, the preset comprehensive characterization parameter value is 0.80, but the above value is not limited thereto, and those skilled in the art can also adjust the value according to actual needs.

[0057] In the embodiment of the present invention, the stable area is a ridge-shaped riverbed surface area with a gentle terrain, a small slope, a low water flow velocity, stable geological conditions, and a low construction difficulty; the scouring area is a ridge-shaped riverbed surface area with a steep terrain, a large slope, a high water flow velocity, complex geological conditions, and a high construction difficulty.

[0058] Specifically, the embodiment of the present invention calculates the comprehensive characterization parameter according to the following formula and sets:

[0059]

[0060] in, represents the comprehensive characterization parameter, H max is the maximum height difference of the ridge-shaped riverbed surface, H min is the minimum height difference of the ridge-shaped riverbed surface, S max is the maximum slope of the ridge-shaped riverbed, S min is the minimum slope of the ridge-shaped riverbed, V max is the maximum flow velocity of water, V min is the minimum flow velocity of water.

[0061] Specifically, in an embodiment of the present invention, under the condition of determining the type of the construction area, a first steel pipe pile is driven into the ridge-shaped riverbed surface to the rock layer using a vibratory hammer, and a comparison result of the influence characterization value of the first steel pipe pile after the driving is obtained with a preset influence characterization value of 0.76 is used to determine whether the first steel pipe pile has an impact on the driving process of the remaining steel pipe piles;

[0062] When the influence characterization value is less than or equal to the preset influence characterization value, it is determined that the first steel pipe pile will not affect the remaining steel pipe pile driving process;

[0063] When the influence characterization value is greater than the preset influence characterization value, it is determined that the first steel pipe pile will have an impact on the remaining steel pipe pile driving process.

[0064] In the embodiment of the present invention, the preset influence characterization value is 0.76, but the above value is not limited thereto, and those skilled in the art can also adjust the value according to actual needs.

[0065] Specifically, the embodiment of the present invention calculates the impact characterization value according to the following formula, setting:

[0066]

[0067] in, Indicates the impact characterization value, The deformation amount representing the height difference of the ridge-shaped riverbed surface, The threshold value of the deformation value representing the height difference of the ridge-shaped riverbed surface is set =10mm, represents the deformation of the ridge-shaped riverbed slope, The deformation threshold representing the slope of the ridge-shaped riverbed surface is set =1mm.

[0068] Specifically, the present invention determines the type of construction area through the comprehensive characterization parameters of the ridge-shaped riverbed surface, adjusts the size and driving spacing of the steel pipe piles, compares the impact characterization value after the driving of the first steel pipe pile to judge the impact on the subsequent driving process, improves the safety of construction, monitors the impact of the driving of the first steel pipe pile in real time, adjusts the subsequent construction strategy, ensures the stability and uniformity of the entire row of steel pipe piles, and thus improves the cofferdam construction efficiency.

[0069] Specifically, under the condition that it is determined that the first steel pipe pile will affect the driving process of the remaining steel pipe piles, the embodiment of the present invention determines that the influence range of the first steel pipe pile is 2 times the steel pipe pile diameter range based on the single deformation value of the ridge-shaped riverbed surface after the steel pipe pile is driven.

[0070] Specifically, the embodiment of the present invention calculates the single deformation value according to the following formula, setting:

[0071]

[0072] in, represents the deformation value of a single root, is the impact characterization value, It is the preset impact representation value.

[0073] Specifically, in an embodiment of the present invention, under the condition that it is determined that the first steel pipe pile will affect the driving process of the remaining steel pipe piles, the vibration frequency of the vibratory hammer is adjusted according to the comparison result of the difference between the influence characterization value and the preset influence characterization value and the preset difference value of 0.55;

[0074] When the difference is less than or equal to the preset difference, it is determined to reduce the vibration frequency of the vibratory hammer to a corresponding value using a first preset frequency adjustment coefficient of 0.96;

[0075] When the difference is greater than the preset difference, it is determined to reduce the vibration frequency of the vibratory hammer to a corresponding value using a second preset frequency adjustment coefficient of 0.91;

[0076] In the embodiment of the present invention, the difference is the difference between the influence characterization value and the preset influence characterization value, that is, the result of subtracting the preset influence characterization value from the influence characterization value.

[0077] In the embodiment of the present invention, the preset difference value is 0.55, but the above value is not limited thereto, and those skilled in the art may also adjust the value according to actual needs.

[0078] In the embodiment of the present invention, the reduced vibration frequency is the product of the vibration frequency and the jth preset frequency adjustment coefficient, where j is 1 or 2, T1 is the first preset frequency adjustment coefficient 0.96, and T2 is the second preset frequency adjustment coefficient 0.91.

[0079] Specifically, the present invention determines the impact of the driving of the first steel pipe pile, determines the impact range based on the deformation value of a single pile, and adjusts the frequency of the vibrating hammer to achieve precise control of the impact of the driving of the steel pipe piles. By adjusting the frequency of the vibrating hammer, the interference with the subsequent driving process of the steel pipe piles is reduced, thereby ensuring the stability of the overall construction.

[0080] See also Figure 3 The flow chart for determining the eligibility of the entire row of steel pipe piles is shown below.

[0081] Specifically, in an embodiment of the present invention, under the condition of determining and adjusting the vibration frequency of the vibratory hammer, a whole row of steel pipe piles is driven into the ridge-shaped riverbed surface, and the qualification of the whole row of steel pipe piles is determined based on the comparison result of the overall uniformity evaluation value of the whole row of steel pipe piles with the overall uniformity evaluation threshold value of 0.82;

[0082] When the overall uniformity evaluation value is less than the overall uniformity evaluation threshold, it is determined that the entire row of steel pipe piles has failed the driving test;

[0083] When the overall uniformity evaluation value is greater than or equal to the overall uniformity evaluation threshold, it is determined that the entire row of steel pipe piles has passed the driving test.

[0084] In the embodiment of the present invention, the overall uniformity evaluation threshold is set to 0.82, but the above value is not limited thereto, and those skilled in the art may also adjust the value according to actual needs.

[0085] Specifically, the embodiment of the present invention calculates the overall uniformity evaluation value according to the following formula, setting:

[0086]

[0087] in, represents the overall uniformity evaluation value, is the total number of steel pipe piles in the entire row, For the The deviation value of steel pipe piles, is the average value of the deviation value of the steel pipe pile.

[0088] Specifically, under the condition that the entire row of steel pipe piles is determined to be unqualified, the embodiment of the present invention determines that the influence range of the entire row of steel pipe piles is 5 times the diameter range of the steel pipe piles based on the entire row deformation value of the ridge-shaped riverbed surface after the entire row of steel pipe piles is driven.

[0089] Specifically, the embodiment of the present invention calculates the entire row deformation value according to the following formula, setting:

[0090]

[0091] in, Represents the deformation value of the entire row, is the overall uniformity evaluation value, is the overall uniformity evaluation threshold.

[0092] Specifically, in an embodiment of the present invention, when it is determined that the driving of an entire row of steel pipe piles is unqualified, the driving spacing of the steel pipe piles is adjusted according to a comparison result of the ratio of the overall uniformity evaluation value to the overall uniformity evaluation threshold and a preset ratio of 0.35;

[0093] When the ratio is less than or equal to the preset ratio, it is determined that the driving spacing of the steel pipe piles is increased to a corresponding value using a first preset spacing adjustment coefficient of 1.03;

[0094] When the ratio is greater than the preset ratio, it is determined that the driving spacing of the steel pipe piles is increased to a corresponding value using a second preset spacing adjustment coefficient of 1.12;

[0095] In the embodiment of the present invention, the ratio is the ratio of the overall uniformity evaluation value to the overall uniformity evaluation threshold.

[0096] In the embodiment of the present invention, the preset ratio is 0.35, but the above value is not limited thereto, and those skilled in the art may also adjust the value according to actual needs.

[0097] In the embodiment of the present invention, the increased insertion and punching spacing is the product of the insertion and punching spacing and the mth preset spacing adjustment coefficient, where m is 1 or 2, U1 is the first preset spacing adjustment coefficient 1.03, and U2 is the second preset spacing adjustment coefficient 1.12.

[0098] Specifically, after all steel pipe piles are driven in, the embodiment of the present invention installs purlins and inner supports on the inner side of the steel pipe piles to complete the cofferdam installation, inserts a steel pipe pile in the center of the cofferdam, and uses a vibratory hammer to vibrate the steel pipe pile in the center of the cofferdam, at which time the vibration frequency is 35 Hz.

[0099] Specifically, the present invention determines whether the steel pipe piles are qualified by calculating the overall uniformity evaluation value of the entire row of steel pipe piles. If they are unqualified, the driving spacing of the steel pipe piles is adjusted to ensure the driving quality of the steel pipe piles on the ridge-shaped riverbed surface. By adjusting the driving spacing, the overall stability is optimized and the riverbed deformation is reduced.

[0100] See also Figure 4 The flow chart for determining the eligibility of cofferdam installation is shown below.

[0101] Specifically, in the embodiment of the present invention, under the condition of vibrating the steel pipe pile at the center of the cofferdam, the eligibility of the cofferdam installation is determined based on the comparison result of the offset distance of the cofferdam after vibration with the preset offset distance of 0.5 mm;

[0102] When the offset distance is less than or equal to the preset offset distance, it is determined that the cofferdam installation is qualified;

[0103] When the offset distance is greater than the preset offset distance, it is determined that the cofferdam installation is unqualified.

[0104] In the embodiment of the present invention, the preset offset distance is set to 0.5 mm, but the above value is not limited thereto, and those skilled in the art may also adjust the value according to actual needs.

[0105] Specifically, the offset distance is measured by a total station.

[0106] Specifically, in the embodiment of the present invention, under the condition that the cofferdam installation is determined to be unqualified, the adjustment influence range is determined according to the comparison result of the relative difference between the offset distance and the preset offset distance and the preset relative difference of 0.26;

[0107] When the relative difference is less than or equal to the preset relative difference, it is determined to reduce the influence range to a corresponding value using a first preset influence range adjustment coefficient of 0.89;

[0108] When the relative difference is greater than the preset relative difference, it is determined to reduce the influence range to a corresponding value using a second preset influence range adjustment coefficient of 0.86;

[0109] The relative difference is the relative difference between the offset distance and a preset offset distance.

[0110] In the embodiment of the present invention, the preset relative difference value is 0.26, but the above value is not limited thereto, and those skilled in the art may also adjust the value according to actual needs.

[0111] In the embodiment of the present invention, the reduced influence range is the product of the influence range and the nth preset influence range adjustment coefficient, where n is 1 or 2, L1 is the first preset influence range adjustment coefficient 0.89, and L2 is the second preset influence range adjustment coefficient 0.86.

[0112] Specifically, in the embodiment of the present invention, water is pumped out of the cofferdam under the condition of adjusting the impact range, and after pumping out the water, the foundation cap steel bars are tied, the foundation cap formwork is installed, and the foundation cap concrete is poured.

[0113] Specifically, the present invention determines the eligibility of the cofferdam installation by vibrating the steel pipe piles and comparing the offset distance. If unqualified, the impact range is adjusted to ensure the accuracy of the cofferdam installation and improve the construction efficiency and quality by adjusting the impact range.

[0114] Thus far, the technical solutions of the present invention have been described in conjunction with 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 may make equivalent changes or substitutions to the relevant technical features, and the technical solutions after such changes or substitutions will fall within the scope of protection of the present invention.

[0115] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that the present invention is susceptible to various modifications and variations. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A method for constructing a steel pipe pile cofferdam with a low pile cap on a ridge-shaped riverbed, characterized in that: include: Obtain geological and hydrological data of the ridge-shaped riverbed surface at the construction site; Determine whether the construction area is a stable zone or a scour zone based on the comprehensive characterization parameters of the ridge-shaped riverbed surface at the construction site; The influence characterization value of the first steel pipe pile driven by the vibratory hammer is used to determine whether the first steel pipe pile has an impact on the driving process of the remaining steel pipe piles; Under the condition that the construction area type is determined, based on the comparison result that the influence characterization value of the first steel pipe pile after driving is greater than the preset influence characterization value, it is determined that the first steel pipe pile has an influence on the driving process of the remaining steel pipe piles; Under the condition that it is determined that the first steel pipe pile has an impact on the driving process of the remaining steel pipe piles, the vibration frequency of the vibratory hammer is reduced based on the difference between the impact effect characterization value and the preset impact effect characterization value; Determining, based on a comparison result of a difference between the impact characterization value and the preset impact characterization value and the preset difference, to reduce the vibration frequency of the vibratory hammer by a first preset frequency adjustment coefficient or a second preset frequency adjustment coefficient; Determine whether the entire row of steel pipe piles is qualified based on the overall uniformity evaluation value of the entire row of steel pipe piles; Under the condition that the entire row of steel pipe piles is determined to be unqualified, the driving spacing of the steel pipe piles is increased based on the ratio of the overall uniformity evaluation value to the overall uniformity evaluation threshold; After all the steel pipe piles are driven, the purlins and inner supports are installed inside the steel pipe piles to complete the cofferdam installation. A steel pipe pile is inserted in the center of the cofferdam. The eligibility of the cofferdam installation is determined based on the offset distance of the cofferdam after vibration. Under the condition that the cofferdam installation is determined to be unqualified, the impact range is reduced based on the relative difference between the offset distance and the preset offset distance; Pump water out of the cofferdam, tie the pedestal reinforcement, install the pedestal formwork, and pour the pedestal concrete.

2. The method for constructing a steel pipe pile cofferdam with a low pile cap on a ridge-shaped riverbed according to claim 1, characterized in that: Based on the comparison results that the comprehensive characterization parameters of the ridge-shaped riverbed surface are less than or equal to the preset comprehensive characterization parameters, the construction area is determined to be a stable area, and the diameter of the steel pipe piles is determined to be 60cm-70cm, and the spacing between the steel pipe piles is determined to be 1.5m.

3. The method for constructing a steel pipe pile cofferdam with a low pile cap on a ridge-shaped riverbed according to claim 1, characterized in that: Based on the comparison result that the comprehensive characterization parameters of the ridge-shaped riverbed surface are greater than the preset comprehensive characterization parameters, the construction area is determined to be an erosion area, and the diameter of the steel pipe piles is determined to be 90cm-100cm, and the spacing between the steel pipe piles is determined to be 1.0m.

4. The method for constructing a steel pipe pile cofferdam with a low pile cap on a ridge-shaped riverbed according to claim 1, characterized in that: Based on the single deformation value of the ridge-shaped riverbed surface after the steel pipe pile is driven, the influence range of the first steel pipe pile is determined to be twice the diameter of the steel pipe pile.

5. The method for constructing a steel pipe pile cofferdam with a low pile cap on a ridge-shaped riverbed according to claim 1, characterized in that: Under the condition of adjusting the vibration frequency of the vibratory hammer, a whole row of steel pipe piles is driven into the ridge-shaped riverbed surface. Based on the comparison result that the overall uniformity evaluation value of the whole row of steel pipe piles is less than the overall uniformity evaluation threshold, it is determined that the whole row of steel pipe piles has failed the driving.

6. The method for constructing a steel pipe pile cofferdam with a low pile cap on a ridge-shaped riverbed according to claim 1, characterized in that: Based on the deformation value of the entire row of ridge-shaped riverbed after the steel pipe piles are driven, the influence range of the entire row of steel pipe piles is determined to be 5 times the diameter range of the steel pipe piles.

7. The method for constructing a steel pipe pile cofferdam with a low pile cap on a ridge-shaped riverbed according to claim 5, characterized in that: Under the condition that the entire row of steel pipe piles is determined to be unqualified, based on the comparison result of the ratio of the overall uniformity evaluation value to the overall uniformity evaluation threshold and the preset ratio, it is determined to increase the driving spacing of the steel pipe piles by the first preset spacing adjustment coefficient or the second preset spacing adjustment coefficient.

8. The method for constructing a steel pipe pile cofferdam with a low pile cap on a ridge-shaped riverbed according to claim 1, characterized in that: Based on the comparison result that the offset distance of the cofferdam after vibration is greater than the preset offset distance, it is determined that the cofferdam installation is unqualified, and based on the comparison result of the relative difference between the offset distance and the preset offset distance and the preset relative difference, it is determined that the influence range is reduced by the first preset influence range adjustment coefficient or the second preset influence range adjustment coefficient.

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