Construction method for positioning and lowering steel casing in complex sea area

Abstract

The invention belongs to the technical field of steel casing construction, and particularly relates to a construction method for positioning and lowering a steel casing in a complex sea area, which comprises the following steps: S1, arranging a percussion drill on a drilling platform, accurately positioning the percussion drill by using an RTK instrument, and enabling the center of a drill bit on the percussion drill to be consistent with the center of a pile position; s2, a drill bit on the percussion drill extends into the seabed to smash the inclined bare rock to be flat; s3, a guide frame is installed, accurate positioning is conducted through an RTK instrument, the center of the guide frame is made to be consistent with the center of the pile position, and the guide frame is connected with a drilling platform; s4, the guide frame is of a double-layer telescopic structure, the distance of the double-layer telescopic structure of the guide frame is shortened to improve the local clamping force when the guide frame clamps the steel casing to connect the multiple sections of steel casing, and the distance of the double-layer telescopic structure of the guide frame is increased to improve the stability of the steel casing in the process that the steel casing is installed to the bare rock; in the two different mounting steps, different clamping effects are provided for the steel casing as required, and the mounting stability and mounting precision of the steel casing are improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of steel casing construction, and particularly relates to a construction method for positioning and lowering of a steel casing in a complex sea area. BACKGROUND

[0002] In recent years, with the vigorous development of marine economy, the construction of cross-sea passages in China is rapidly advancing in the direction of "deep water, large span and clustering". As the core temporary structure of deep water foundation construction, the positioning and lowering technology of steel casings is directly related to the quality of pile foundation construction and engineering safety. As a key structure of deep water foundation construction, steel casings are widely used in pile foundation construction for guiding positioning and protection. Especially in complex sea area environment, in view of the challenges of water depth, strong wind, rough waves, high flow rate, bare rock geology and the like, the accurate positioning and safe lowering of steel casings face many technical challenges. However, the accurate positioning and control of the verticality of steel casings in construction is still a technical problem, especially in complex sea areas, how to quickly and accurately lower the steel casing to the designed position is the key to improving construction efficiency and ensuring safety. Therefore, how to solve the accurate positioning and verticality of the steel casing has become a technical problem to be solved in the construction of offshore bridges.

[0003] Especially in the sea area with complex sea conditions, since the installation requirements of the guide frame are different at different installation stages of the steel casing, when the steel casing is initially extended below the sea level, the position does not need to be adjusted accurately since the distance from the installation position is far, and at this stage, multiple steel casings need to be installed on the first steel casing, so the guide frame needs to provide clamping force to the steel casing, and when the multiple steel casings are all installed, they need to be gradually deepened below the sea level, so the installation position gradually approaches the seabed, and the requirement for the guiding accuracy of the guide frame is higher, and the guide frame needs to provide more stable guiding accuracy to avoid the influence of large waves on the steel casing, and the existing guide frame cannot provide different requirements for the steel casing at two different installation steps. Based on this, a construction method for positioning and lowering of a steel casing in a complex sea area is provided. SUMMARY

[0004] To solve the above problems in the prior art, the application provides a construction method for positioning and lowering of a steel casing in a complex sea area.

[0005] The object of the application can be achieved by the following technical solutions: The construction method for positioning and lowering of a steel casing in a complex sea area provided by the application comprises the following steps: S1: setting an impact drill on a drilling platform, and using an RTK instrument to accurately position the center of the drill bit on the impact drill to be consistent with the center of the pile position; S2: the drill bit on the percussion drill is extended into the seabed and the seabed is tilted and leveled with bare rock; S3: a guide frame is installed, accurate positioning is performed through an RTK instrument, the center of the guide frame is made consistent with the center of the pile position, and the guide frame is connected with the drilling platform; S4: the guide frame is a double-layer telescopic structure, the guide frame clamps the steel casing and shortens the distance of the double-layer telescopic structure of the guide frame when connecting multiple steel casings to improve the local clamping force, and the distance of the double-layer telescopic structure of the guide frame is lengthened during installation of the steel casing to the bare rock to improve the stability of the steel casing.

[0006] As a further scheme of the present application, in the step S4, the double-layer telescopic structure of the guide frame comprises an upper guide plate and a lower guide plate, guide wheels are arranged at equal intervals on the inner side of the center holes of the upper guide plate and the lower guide plate, a plurality of hydraulic rods are connected between the upper guide plate and the lower guide plate, the hydraulic rods are shortened to move the upper guide plate and the lower guide plate closer when connecting the steel casing, and the hydraulic rods are lengthened to move the upper guide plate and the lower guide plate away when installing the steel casing.

[0007] As a further scheme of the present application, the plurality of hydraulic rods are arranged obliquely between the upper guide plate and the lower guide plate.

[0008] As a further scheme of the present application, in the step S2, the diameter of the drill bit is 40cm-80cm larger than the diameter of the steel casing.

[0009] As a further scheme of the present application, in the step S4, when connecting the steel casing, the first steel casing is clamped on the guide frame; the remaining steel casings are welded and connected with the first steel casing, and the lowering of the steel casing is completed through a vibration hammer.

[0010] As a further scheme of the present application, during lowering of the steel casing, the verticality of the steel casing is controlled by adjusting the guide wheels.

[0011] As a further scheme of the present application, in the step S4, when lowering the steel casing, the water entry depth of the first steel casing is about 1m; when lowering the remaining steel casings, the lowering construction is performed when the tide is receding to the low tide level, and the guide wheels are used for accurate positioning and verticality control of the steel casing during lowering.

[0012] As a further scheme of the present application, in the step S3, the guide frame is installed while a ladder and a guardrail are installed on the drilling platform.

[0013] The present application has the following beneficial effects: (1) The inclination bare rock leveling operation is carried out by using the percussion drill, the problem of the inclination and deformation of the steel casing caused by the complex geological conditions can be effectively prevented, the RTK instrument can provide more accurate positioning accuracy through the differential calculation between the base station and the mobile station, the guide frame can accurately position the steel casing at the accurate position, the eight guide wheels arranged on the guide frame can effectively control the perpendicularity of the steel casing, and finally the accurate positioning of the steel casing is realized, and the problem of the positioning and the perpendicularity control of the steel casing in the complex sea conditions is solved.

[0014] (2) By shortening the clamping distance of the double-layer telescopic structure when connecting the steel casings, two constraint points are provided in a shorter longitudinal distance, the constraint points are more concentrated for the steel casings, the initial shaking and the slight deviation of the steel casings can be more effectively inhibited, and the foundation for the subsequent stable lowering is laid; when the steel casings are installed to the seabed, the distance between the double-layer telescopic structures of the guide frame is increased at this stage, the anti-overturning effect of the guide frame on the steel casings is better, and since the verticality of the steel casings needs to be accurately adjusted at this stage, the distance between the double-layer telescopic structures is increased, so that the verticality of the steel casings can be more conveniently adjusted, and the accuracy of the installation of the steel casings can be ensured. BRIEF DESCRIPTION OF DRAWINGS

[0015] In order to facilitate the understanding of those skilled in the art, the present application will be further described below with reference to the accompanying drawings.

[0016] Figure 1 is a steel casing lowering construction drawing in the embodiment of the present application; Figure 2 is a percussion drill inclination bare rock leveling operation drawing in the embodiment of the present application; Figure 3 is a guide frame ladder arrangement drawing in the embodiment of the present application; Figure 4 is a guide frame guardrail arrangement drawing in the embodiment of the present application; The reference signs are as follows: 1, guide frame; 2, drilling platform; 3, remaining steel casing; 4, first section steel casing; 5, vibration hammer; 6, guide wheel; 7, drill bit; 8, percussion drill; 9, ladder; 10, guardrail. DETAILED DESCRIPTION

[0017] In order to further illustrate the technical means and effects adopted by the present application to achieve the predetermined object, the specific embodiments, structures, features and effects according to the present application are described in detail below with reference to the accompanying drawings and preferred embodiments.

[0018] As Figure 1 -Figure 4 As shown, the construction method for positioning and lowering a steel casing in a complex sea area according to the present application comprises the following steps: S1: An impact drill 8 is arranged on the drilling platform 2, and the impact drill 8 is precisely positioned by using an RTK instrument so that the center of the drill bit 7 on the impact drill 8 is consistent with the center of the pile position; S2: The drill bit 7 on the impact drill 8 is inserted into the seabed and the inclined bare rock is flattened; S3: The guide frame 1 is installed, and the guide frame 1 is precisely positioned by using the RTK instrument so that the center of the guide frame 1 is consistent with the center of the pile position, and the guide frame 1 is connected with the drilling platform 2; S4: The guide frame 1 has a double-layer telescopic structure, the guide frame 1 clamps the steel casing and shortens the distance of the double-layer telescopic structure of the guide frame 1 to improve the local clamping force when connecting multiple steel casings, and the distance of the double-layer telescopic structure of the guide frame 1 is lengthened to improve the stability of the steel casing during the installation of the steel casing to the bare rock.

[0019] In the above construction scheme, the inclined bare rock is first flattened by using the impact drill 8, and the diameter of the drill bit 7 should be 40cm to 80cm larger than the diameter of the steel casing during the flattening operation. The steel casing construction is performed after the inclined bare rock is flattened, which can effectively prevent the problems of casing deflection and deformation caused by complex geological conditions. In this embodiment, the diameter of the steel casing is 2.3m, and a drill bit 7 with a diameter of 3m is used for flattening operation. The RTK instrument can provide more accurate positioning accuracy, and the guide frame 1 can be accurately positioned at the correct position by using the RTK. The double-layer eight guide wheels 6 arranged on the guide frame 1 can effectively control the perpendicularity of the steel casing. In summary, the inclined bare rock is flattened by using the impact drill 8, the guide frame 1 is precisely positioned by using the RTK instrument, and the guide wheels 6 on the guide frame 1 guide the steel casing, which can realize the precise positioning of the steel casing and finally solve the problem of difficult positioning and perpendicularity control of the steel casing in complex sea areas.

[0020] At the same time, since the installation requirements of the guide frame 1 are different at different installation stages of the steel casing in the sea area with complex sea conditions, the distance from the installation position is far when the steel casing is initially inserted below the sea level, so accurate position adjustment is not required at this stage. However, the remaining steel casings 3 need to be installed on the first steel casing 4 at this stage, so the clamping force of the guide frame 1 on the steel casing needs to be ensured. After the installation of the remaining steel casings 3 is completed, the steel casing needs to be gradually inserted below the sea level, so the guide accuracy of the guide frame 1 needs to be higher, the influence of the steel casing by the large waves needs to be avoided, and the guide frame 1 needs to provide more stable guide accuracy. The guide frame 1 needs to provide different clamping effects on the steel casing at different installation steps according to the needs; Since the first steel casing 4 needs to be clamped on the guide frame 1 first before the subsequent remaining steel casings 3 are connected to the first steel casing 4, the double telescopic structure of the guide frame 1 has a smaller clamping area during the steel casing connection stage. By shortening the clamping interval of the double telescopic structure, two constraint points are provided in a shorter longitudinal distance, which can more effectively suppress the initial shaking and slight deviation of the steel casing itself, laying a good foundation for subsequent stable lowering. It can be understood as providing a tighter hoop at the entrance. Moreover, the contact points of the guide wheels 6 with the steel casing are more concentrated in the initial stage, which is more sensitive to slight displacement or inclination, which is conducive to timely discovering and correcting deviations. After the construction is completed, the guide frame 1 is shortened in interval, which is helpful for folding the structure and facilitating hoisting, disassembly or transfer of equipment.

[0021] After the steel casings are connected, and when the steel casings are installed to the seabed, the steel casings are long and contact with seawater in a large area after being connected, so they are subjected to a larger horizontal force. In this stage, the interval of the double telescopic structure of the guide frame 1 is increased, and the guide frame 1 provides a better anti-overturning effect on the steel casings. At the same time, since the verticality of the steel casings needs to be accurately adjusted at this stage, the increased interval of the double telescopic structure can more conveniently fine-tune the verticality of the steel casings, thereby ensuring the accuracy of the installation of the steel casings.

[0022] As a further scheme of the present application, in step S4, the double telescopic structure of the guide frame 1 comprises an upper guide plate and a lower guide plate, the inner sides of the center holes of the upper guide plate and the lower guide plate are each provided with guide wheels 6 at equal intervals, a plurality of hydraulic rods are connected between the upper guide plate and the lower guide plate, the hydraulic rods are shortened to move the upper guide plate and the lower guide plate closer during the connection of the steel casings, the hydraulic rods are elongated to move the upper guide plate and the lower guide plate away during the installation of the steel casings, and the plurality of hydraulic rods are each inclinedly arranged between the upper guide plate and the lower guide plate. The adjacent two hydraulic rods are connected in staggered inclination, so that the two hydraulic rods and the upper guide plate and the lower guide plate form a stable triangular structure. When a plurality of groups of hydraulic rods are provided, the triangular structures formed by the two adjacent hydraulic rods in each group can avoid the horizontal deviation of the upper guide plate and the lower guide plate of the guide frame 1. The adjustment accuracy of the steel casings can be improved.

[0023] As a further scheme of the present application, in step S4, the first steel casing 4 is clamped on the guide frame 1 during the connection of the steel casings; the remaining steel casings 3 are welded and connected to the first steel casing 4, and the steel casings are lowered by the vibration hammer 5.

[0024] As a further scheme of the present application, in the process of lowering the steel casing, the verticality of the steel casing is controlled by adjusting the guide wheels 6. The inside of the center hole of the upper and lower guide plates is provided with a guide wheel 6, the guide wheel 6 can adjust the angle and the telescopic distance, the two layers of guide wheels 6 are used for guiding, there are 4 guide wheels 6 in a single layer, and there are totally 8 guide wheels 6, the verticality of the steel casing is adjusted by the 8 guide wheels 6, after the steel casing is lowered to the position, the steel casing is welded and fixed on the guide frame 1 by the two groups of fixed guide rods, and each group of the fixed guide rods is provided with 4 fixed guide rods, which are arranged alternately with the guide wheels 6.

[0025] As a further scheme of the present application, in step S4, when the steel casing is lowered, the water entry depth of the first section steel casing 4 is about 1m; when the remaining steel casings 3 are lowered, the lowering construction is performed when the tide is receding to the low tide level, and the guide wheels 6 are used for accurately positioning the steel casing and controlling the verticality thereof during the lowering. In the embodiment, the length of the first section steel casing 4 is 13m, the first section steel casing 4 is lowered when the tide is receding, and the maximum water entry depth of the first section steel casing 4 is 1.2m, so that the influence of the rapid flow on the verticality of the steel casing during the lowering can be reduced. When the remaining steel casings 3 are lowered, the lowering construction is performed when the tide is receding to the low tide level, the guide wheels 6 are used for accurately positioning the steel casing and controlling the verticality thereof during the lowering, the steel casing is lowered to the bare rock, the verticality of the steel casing is measured again, and the vibration hammer 5 is inserted and driven into the steel casing after the verticality meets the requirements.

[0026] As a further scheme of the present application, in step S3, the guide frame 1 is installed, and the crawling ladder 9 and the guardrail 10 are simultaneously installed on the drilling platform 2.

[0027] The above is only a preferred embodiment of the present application, and does not limit the present application in any form. Although the present application has been disclosed as the above preferred embodiment, it is not intended to limit the present application. Any person skilled in the art can make some changes or modifications to the above disclosed technical content to obtain equivalent embodiments with equivalent changes, as long as the changes or modifications do not deviate from the technical scheme of the present application. Any modification, change, equivalent change and modification of the above embodiment based on the technical essence of the present application are still within the scope of the technical scheme of the present application.

Claims

1. A construction method for positioning and lowering a steel casing in a complex marine site, characterized in that: The method comprises the following steps: S1: setting an impact drill on a drilling platform, accurately positioning the impact drill by using an RTK instrument, and aligning the center of a drill bit on the impact drill with the center of a pile position; S2: extending the drill bit on the impact drill into the seabed and flattening the seabed inclined bare rock; S3: installing a guide frame, accurately positioning the guide frame by using the RTK instrument, aligning the center of the guide frame with the center of the pile position, and connecting the guide frame with the drilling platform; S4: the guide frame is a double-layer telescopic structure, the guide frame clamps a steel casing and shortens the distance of the double-layer telescopic structure of the guide frame when connecting multiple steel casings to improve the local clamping force, and the distance of the double-layer telescopic structure of the guide frame is lengthened during the installation of the steel casing to the bare rock to improve the stability of the steel casing.

2. The method according to claim 1, wherein: In the step S4, the double-layer telescopic structure of the guide frame comprises an upper guide plate and a lower guide plate, guide wheels are arranged at equal intervals on the inner sides of the center holes of the upper guide plate and the lower guide plate, a plurality of hydraulic rods are connected between the upper guide plate and the lower guide plate, the hydraulic rods are shortened to move the upper guide plate and the lower guide plate closer when connecting the steel casings, and the hydraulic rods are lengthened to move the upper guide plate and the lower guide plate away when installing the steel casings.

3. The method according to claim 2, wherein: The plurality of hydraulic rods are inclined between the upper guide plate and the lower guide plate.

4. The method according to claim 1, wherein: In the step S2, the diameter of the drill bit is 40cm-80cm larger than the diameter of the steel casing.

5. The method according to claim 2, wherein: In the step S4, when connecting the steel casings, the first steel casing is clamped on the guide frame; the remaining steel casings are welded and connected with the first steel casing, and the lowering of the steel casings is completed by a vibration hammer.

6. The method according to claim 5, wherein: During the lowering of the steel casings, the verticality of the steel casings is controlled by adjusting the guide wheels.

7. The method according to claim 6, wherein: In the step S4, when lowering the steel casings, the water entry depth of the first steel casing is about 1m; when lowering the remaining steel casings, the lowering construction is performed when the tide recedes to the low tide level, and the guide wheels are used to accurately position and control the verticality of the steel casings during the lowering.

8. The method according to claim 1, wherein the method further comprises the steps of: providing a plurality of steel casings; and positioning the plurality of steel casings in the complex marine region. In the step S3, the guide frame is installed while a ladder and a guardrail are simultaneously installed on the drilling platform.

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