阅读说明：本技术 海上嵌岩桩基础的一次***开挖成型方法 (One-time blasting excavation forming method for offshore rock-socketed pile foundation ) 是由 卢文波 陈明 朱子晗 严鹏 王高辉 于 2020-06-11 设计创作，主要内容包括：本发明公开了一种海上嵌岩桩基础的一次爆破开挖成型方法,本方法的施工程序为：钻机平台架设；地质钻机造孔；套管护孔；钻孔内装炸药起爆；下组合嵌岩桩钢管；钢管内清渣；混凝土灌注。其中,大直径中间空孔不装炸药,轮廓孔内连续装炸药,辅助孔及掏槽孔采用分段间隔装炸药并在掏槽孔每段间隔处放置铁球；采用分层分段起爆方式。本发明采用爆破方法开挖的方法,一次爆破开挖成型：轮廓孔可以定向成缝；掏槽孔内放置的铁球具有聚能效果,可以加强内部爆破效果；中心掏槽孔起爆后有推渣的作用。该发明可有效解决目前海上嵌岩桩基坑开挖方法中大孔径钻机难以及时就位的问题,该方法具有工艺简单,使用机械常规,施工效率高,施工成本低等优点。(The invention discloses a one-time blasting excavation forming method of an offshore rock-socketed pile foundation, which comprises the following construction procedures: erecting a drilling machine platform; forming holes by a geological drilling machine; protecting the hole of the sleeve; detonating explosive filled in the drill hole; a lower combined socketed pile steel pipe; removing slag in the steel pipe; and (5) pouring concrete. Wherein, the middle hollow hole with large diameter is not filled with explosive, the contour hole is filled with explosive continuously, the auxiliary holes and the cut holes are filled with explosive at intervals in sections, and iron balls are placed at the intervals of each section of the cut holes; adopts a layered and segmented detonating mode. The invention adopts a blasting method for excavation, and the method comprises the following steps of blasting excavation molding: the contour holes may be oriented as slots; the iron balls placed in the cut holes have an energy gathering effect and can enhance the internal blasting effect; the central cut hole has the function of pushing slag after being detonated. The method can effectively solve the problem that a large-aperture drilling machine is difficult to place in time in the existing offshore rock-socketed pile foundation pit excavation method, and has the advantages of simple process, conventional use machinery, high construction efficiency, low construction cost and the like.)

1. A one-time blasting excavation forming method of an offshore rock-socketed pile foundation is characterized by comprising the following steps: the method comprises the following steps:

s1, erecting a drilling machine platform, drilling contour holes, auxiliary holes and cut holes at the preset positions of the foundation pit to the specified height according to blasting design, and protecting the holes by using sleeves;

s2, explosive is filled according to the blasting design, the explosive is not filled in the central hollow hole, the explosive is continuously filled in the contour hole, the explosive is filled in the auxiliary holes and the cut holes at intervals in sections, and energy collecting devices are arranged at intervals of each section of the cut holes and can strengthen the blasting effect, so that a smaller blasting block is formed after blasting;

s3, networking and detonating, wherein a layered and segmented detonating mode is adopted for detonating according to the blasting design and the blasting method, the profile holes, the auxiliary holes and the cut holes are detonated in a segmented mode from top to bottom, and the profile holes, the auxiliary control holes and the cut holes among the holes are detonated layer by layer;

s4, positioning and sinking the combined rock-socketed pile steel pipe to a specified position, and removing sludge and weathered sand in a weathered layer in the steel pipe;

s5, pouring concrete;

the blasting excavation forming method can adopt presplitting blasting or smooth blasting; when presplitting blasting is adopted, the contour hole in the step S2 is a presplitting hole; when the smooth blasting is adopted, the contour hole in the step S2 is a smooth blasting hole.

2. The offshore rock-socketed pile foundation pit blasting excavation method is characterized by comprising the following steps of: in the step S2, the center of the cut hole is spaced from the center of the hollow hole by the center R₁0.3 to 0.5 m; distance R between the center of the auxiliary hole and the center of the central hollow hole₂1.5-2.0 m; distance R between the hole center of the contour hole and the hole center of the central hollow hole₃2.5 to 4.2 m.

3. The offshore rock-socketed pile foundation pit blasting excavation method according to claim 1 or 2, characterized by comprising the following steps: in the step S2, the aperture of the cut hole and the auxiliary hole is not less than 140mm, and the ultra-deep length of the hole depth is 0.1 time of the pile well depth; the aperture of the contour hole is not less than 100 mm; the aperture of the central hollow hole is 210-250 mm, and the ultra-deep length of the hole depth is 0.1-0.15 times of the pile well depth.

4. The offshore rock-socketed pile foundation pit blasting excavation method according to claim 1 or 2, characterized by comprising the following steps: in the step S3, the explosive diameters of the cut holes and the auxiliary holes are not less than 100mm, and the explosive diameters of the contour holes are not less than 70 mm; the central hollow hole is not filled with explosive, and an empty surface is created for the cut hole.

5. The offshore rock-socketed pile foundation pit blasting excavation method is characterized by comprising the following steps: in the step S3, the explosive diameters of the cut holes and the auxiliary holes are not less than 100mm, and the explosive diameters of the contour holes are not less than 70 mm; the central hollow hole is not filled with explosive, and an empty surface is created for the cut hole.

6. The offshore rock-socketed pile foundation pit blasting excavation method is characterized in that: in the step S3, the contour holes are filled with explosives continuously, and the auxiliary holes and the cut holes are filled with explosives at intervals; iron balls are placed at the interval of charging in the cut holes to serve as energy gathering devices, local energy gathering blasting is formed, and blasting effect is improved.

7. The offshore rock-socketed pile foundation pit blasting excavation method is characterized in that: in the step S3, the plugs of the charging spacing section and the blast hole blocking section may be graded sand, and appropriate coarse sand and fine sand are mixed and directly poured into the blast hole.

8. The offshore rock-socketed pile foundation pit blasting excavation method is characterized in that: in the step S4, the detonation mode adopts layered and segmented detonation, each segment is 3-5 m, 2-3 levels of cut grooves are formed, and the detonation is carried out sequentially from top to bottom; when presplitting blasting is adopted among the contour holes, the auxiliary holes and the cut holes on the same layer, the presplitting holes are detonated firstly, and the cut holes and the auxiliary holes are detonated layer by layer; when smooth blasting is adopted, the cut holes are detonated layer by layer, then the blasting hole is detonated, and finally the auxiliary hole is detonated.

Technical Field

The invention belongs to the technical field of foundation pit excavation of offshore wind power foundations, and particularly relates to a one-time blasting excavation forming method of an offshore rock-socketed pile foundation.

Background

In recent years, as resource consumption is increased and non-renewable energy is reduced, the development and utilization of clean energy are receiving more and more attention. Offshore wind power occupies an important proportion in the development and utilization of clean energy due to the characteristics of abundant resources, high power generation efficiency, suitability for large-scale development and the like.

Offshore wind power often needs to face severe conditions including typhoon, wave shock and the like, and due to the fact that a covering layer often covers seabed bedrock, geological conditions of the bedrock are complex, and a lot of difficulties are added to pile foundation construction of a wind turbine generator. At present, the commonly used fixed foundation of the offshore wind turbine comprises a rock-socketed pile foundation and a gravity type pile foundation, and the rock-socketed pile foundation is popular due to simple structure, low manufacturing cost and high reliability. At present, a large-diameter drilling machine is mostly adopted for one-time excavation forming of a large-diameter socketed pile foundation pit, but the size of the socketed pile foundation pit is increased day by day along with the increase of the installed capacity of wind power, and the domestic large-diameter drilling machine meeting the requirement of offshore operation at present meets the shortage of supply and demand, so that the construction progress is seriously influenced; and because of the influence of the lithology of the complex stratum in the deep part of the covering layer, the steel pipe pile driving process easily causes the inner and outer rolling mouths of the pipe wall at the bottom part, the subsequent construction steps such as mechanical expanding excavation and the like are influenced, the construction difficulty is large on the whole, and the construction period is long. However, during construction in a complex offshore environment, the construction is greatly influenced by weather, the effective construction period is short, and an economical and efficient foundation pit excavation method needs to be adopted to meet the construction requirement of the offshore wind generating set.

At present, the existing excavation mode of the rock-socketed pile foundation has a plurality of new ideas, but the cost is difficult to be reduced and the construction progress is accelerated while the structural design and construction requirements are effectively met. The 'construction process of an offshore wind power foundation implanted rock-socketed single pile' with the patent number of CN 108842807A adopts platform assistance positioning, and a steel casing carries out rock-socketed construction, can effectively improve the horizontal resistance and the resistance to plucking ability of the rock-socketed pile, but the complex operation needs the cooperation construction of a main crane ship and an auxiliary crane ship, and the construction cycle is longer, and the cost is higher.

The patent No. CN 106088140A 'a rock-based seabed offshore wind turbine rock-socketed single-pile foundation construction process' proposes a construction process of 'driving-drilling-driving', firstly, a hydraulic impact hammer is used for sinking a pile to a certain depth, then, drilling and excavating are carried out in the pile until the designed elevation is reached, and finally, the hydraulic impact hammer is used for sinking the pile to the designed elevation.

Therefore, the method for excavating the offshore rock-socketed pile foundation pit, which is independent of a large-diameter drilling machine, convenient, rapid, economic and reliable, and can adapt to any diameter, has very important significance.

Disclosure of Invention

In order to solve the problems, the invention aims to provide a blasting excavation method for a foundation pit of an offshore rock-socketed pile, which mainly adopts a blasting excavation method; the method has the advantages of simple process, conventional use machinery, high construction efficiency and low construction cost.

In order to achieve the purpose, the one-time blasting excavation forming method of the offshore rock-socketed pile foundation provided by the invention comprises the following steps of:

s1, erecting a drilling machine platform, drilling contour holes, auxiliary holes and cut holes at the preset positions of the foundation pit to the specified height according to blasting design, and protecting the holes by using sleeves;

s2, explosive is filled according to the blasting design, the explosive is not filled in the central hollow hole, the explosive is continuously filled in the contour hole, the explosive is filled in the auxiliary holes and the cut holes at intervals in sections, and energy collecting devices are arranged at intervals of each section of the cut holes and can strengthen the blasting effect, so that a smaller blasting block is formed after blasting;

s3, networking and detonating, wherein the detonating is carried out in a layered and segmented detonating mode according to the blasting design and the blasting method, the detonating is carried out in segments from bottom to top in the holes, and the detonating is carried out layer by layer between the holes;

s4, positioning and sinking the combined rock-socketed pile steel pipe to a specified position, and removing sludge and weathered sand in a weathered layer in the steel pipe;

s5, pouring concrete;

the blasting excavation method can adopt presplitting blasting or smooth blasting, and when presplitting blasting is adopted, the contour hole in S2 is a presplitting hole; when the smooth blasting is adopted, the contour hole is the smooth blasting hole in S2.

Preferably, in the step S2, the distance between the external undercut hole and the central hollow hole R is set₁0.3 to 0.5 m; distance R between auxiliary hole and central hole₂1.5-2.0 m; distance R between contour hole and central hole₃2.5-4.2 m;

further, in the step S2, the aperture of the cut hole and the auxiliary hole is not less than 140mm, and the ultra-depth is 0.1 times of the pile well depth; the aperture of the contour hole is not less than 100 mm; the aperture of the central hollow hole is 210-250 mm, and the ultra-depth is 0.1-0.15 times of the pile well depth;

furthermore, in the step S3, the explosive diameters in the cut holes and the auxiliary holes are not less than 100mm, and the explosive diameters in the contour holes are not less than 70 mm; the center hollow hole is not filled with explosive, and an empty surface is created for the cut hole;

furthermore, in step S3, the contour holes are continuously filled with explosives, and the rest of the blastholes are filled with explosives at intervals; iron balls are placed at intervals in the cut holes to serve as energy gathering devices, local energy gathering blasting is formed, and blasting effect is improved;

furthermore, the plug segment plug in the step S3 may adopt graded sand, and appropriate coarse sand and fine sand are mixed and directly poured into the blast hole;

furthermore, in the step S4, the detonation mode adopts layered and segmented detonation, each segment is 3-5 m, is divided into 2-3 levels of undercuts, and is detonated sequentially according to a certain time difference from top to bottom; when presplitting blasting is adopted among different holes in the same layer, the presplitting holes are firstly detonated, and the auxiliary holes of the cut holes are detonated layer by layer; when smooth blasting is adopted, the cut holes are detonated layer by layer, then the blasting hole is detonated, and finally the auxiliary hole is detonated.

Compared with the prior art, the invention has the following innovation points and advantages:

(1) the invention adopts a blasting excavation mode, the construction process is simple, and the operation is simple and convenient;

(2) the method is not dependent on a large-diameter drilling machine, can avoid delay and inconvenience caused by difficulty in timely positioning of the large drilling machine, can meet the requirements of excavation of foundation pits with various different diameters, and is high in applicability;

(3) the invention uses the method of sectional cutting of the large-diameter blast hole, uses the energy-gathered blasting in the cut hole, can improve the blasting excavation efficiency and effect, and simultaneously, the contour hole is oriented to form a seam, so that the blasting excavation can be formed at one time, and the excavation efficiency is improved. The central large-diameter hollow hole can create a blank face for blasting, so that a slag pushing effect is achieved, and the condition that root bottoms do not remain after blasting excavation is ensured.

In conclusion, the method can effectively carry out the excavation of the offshore rock-socketed pile foundation pit with any diameter, greatly reduce the dependence on a large-aperture drilling machine, accelerate the construction progress, reduce the abrasion of mechanical equipment and the labor intensity of workers, has high economic benefit, and can be popularized and applied in the relevant fields of offshore foundation pit excavation and the like.

Drawings

FIG. 1 is a schematic construction cross-sectional view of the blasting excavation forming method of the present invention;

FIG. 2 is a schematic construction section view of the blasting excavation forming method of the present invention;

in the figure: 1. a central void; 2. cutting holes; 3. an auxiliary hole; 4. a contour hole; 5. an explosive; 6. an inner ring blocking section; 7. iron A ball.

Detailed Description

In order to make the technical means, the creation features, the achievement purposes and the effects of the invention easy to understand, the following description is further used for explaining how to implement the invention with the accompanying drawings and the detailed implementation modes.

In the excavation engineering of a foundation pit of a marine socketed pile with a large diameter, the diameter of the foundation pit is 8m, the depth of the foundation pit is 20m, a covering layer is thin, and bedrocks are mainly medium and strong weathered rocks; the engineering construction environment has large tidal range and large wave, the construction needs high speed and the construction cost is low, great difficulty is brought to the construction, and due to the problems that a large-diameter rotary machine has requirements on the use environment and is difficult to allocate, the marine rock-socketed pile foundation pit blasting excavation method specifically adopts a presplitting blasting excavation method.

The invention discloses a blasting excavation method for a foundation pit of an offshore rock-socketed pile, which comprises the following concrete excavation steps:

s1, erecting a drilling machine platform, drilling a contour hole 4, an auxiliary hole 3 and a cut hole 2 at a preset position of the foundation pit to a specified height according to blasting design, and protecting the hole by using a sleeve;

s2, explosive 5 is loaded according to the blasting design, the explosive 5 is not loaded in the central hollow hole 1 (the middle large-diameter hollow hole), the explosive 5 is continuously loaded in the contour hole 4, the auxiliary holes 3 and the cut holes 2 are loaded with the explosive 5 at intervals in sections, and energy collecting devices are placed at the intervals of each section of the cut holes 2, so that the blasting effect can be enhanced by the energy collecting devices, and a smaller blasting block is formed after blasting;

s3, networking and detonating, wherein the detonating is carried out in a layered and segmented detonating mode according to the blasting design and the blasting method, the detonating is carried out in segments from bottom to top in the holes, and the detonating is carried out layer by layer between the holes;

s4, positioning and sinking the combined rock-socketed pile steel pipe to a specified position, and removing sludge and weathered sand in a weathered layer in the steel pipe;

and S5, pouring concrete.

Wherein, in step S2, the outer cut holes 2 are spaced from the central cut hole 2R₁Is 0.5 m; the auxiliary hole 3 is at a distance R from the central cut hole 2₂Is 2.0 m; the distance R between the contour hole 4 and the central cut hole 2₃Is 4.0 m;

wherein, in the step S2, the aperture of the cut hole 2 and the auxiliary hole 3 is 140mm, and the ultra-deep is 2 m; the aperture of the contour hole 4 is 110 mm; the aperture of the central hollow hole 1 is 250mm, the ultra-depth is 2m, and the root bottom is ensured not to be remained;

in the step S3, the explosive diameter in the cut hole 2 is 100mm, the explosive diameter in the auxiliary hole 3 is 100mm, and the explosive diameter in the contour hole 4 is 70 mm;

in step S3, continuously loading explosives 5 into contour holes 4, and loading the explosives 5 into the rest blast holes at intervals; iron balls 7 are placed at intervals in the cut holes 2 to serve as energy-gathering devices, local energy-gathering blasting is formed, and blasting effect is improved;

in the step S3, the plug of the inner ring plugging section 6 can adopt graded sand, and proper coarse sand and fine sand are mixed and then directly poured into the blast hole;

in the step S4, 3-level undermining is performed from top to bottom, the detonation mode adopts layered and segmented detonation, each segment is 5m, and the detonation is performed sequentially according to a certain time difference from top to bottom; between different holes on the same layer, the pre-split holes are firstly detonated, and the cut holes 2 and the auxiliary holes 3 are detonated layer by layer;

finally, the above description is only an embodiment of the present invention, and not intended to limit the scope of the present invention, and all equivalent structures or equivalent flow transformations made by using the contents of the specification and the drawings, or applied directly or indirectly to other related technical fields, are included in the scope of the present invention.