Offshore drilling method using a hollowed-out backfilling pile section

Abstract

The present application relates to the technical field of offshore foundation construction, and discloses a method for drilling into a collapsed backfilling section of a near-shore rock-filled hole, comprising the following construction steps: 1) forming a concrete slab on a rock-filled layer at a construction site; 2) drilling a pre-drilled hole section in the concrete slab by a rotary drilling machine; 3) inserting a casing into the pre-drilled hole section; 4) rotating the casing into the rock-filled layer by the rotary drilling machine, and forming a collapsed area between the concrete slab and the rock-filled layer; 5) drilling a peripheral hole in the concrete slab and connecting the peripheral hole with the collapsed area; 6) backfilling the peripheral hole with peripheral clay to fill the collapsed area; 7) the rock-filled layer has in-hole rock filling and in-hole clay backfilling; 8) extruding the in-hole clay into the gap of the in-hole rock filling by a punching hammer in the casing, and synchronously crushing the in-hole rock filling until the punching hammer penetrates the rock-filled layer to form a rock-filled hole section, thereby avoiding further expansion of the collapsed area and realizing stable and efficient drilling construction effect.

Description

Technical Field

[0001] This invention relates to the technical field of near-shore foundation construction, and more specifically, to a method for drilling and backfilling near-shore rockfill sections where the casing collapses. Background Technology

[0002] Near-shore rockfill layers are a common complex foundation condition, characterized by loose structure, high porosity, and strong permeability. To ensure the stability of the hole formation in the rockfill layer and prevent the hole wall from collapsing, it is generally necessary to install a casing in advance. The backfilling effect caused by the collapse of the outer perimeter of the casing affects the overall quality of the foundation construction.

[0003] In existing technologies, the treatment of collapsed areas is mostly passive, such as simply backfilling or ignoring the impact of collapsed areas. This causes the casing to tilt, sink, or even twist due to impact and vibration during subsequent construction operations, which seriously affects the quality of hole formation and construction efficiency.

[0004] Some people use simple backfill materials such as ordinary clay, silt or sand, and the backfilling method is mainly manual or mechanical dumping. This cannot ensure that the material fills the collapsed area densely, nor can it penetrate into the internal pores. The backfilling effect is poor, and the collapse phenomenon occurs repeatedly.

[0005] In addition, in the existing construction process, when the punching hammer operates inside the casing, the vibration waves generated will continuously disturb the connection between the casing and the stratum, leading to the expansion of the collapse zone and the instability of the casing. There is a lack of an intermediate process that can consolidate the external environment of the casing in one go before operating inside the casing, making it difficult to achieve effective anchoring of the casing in near-shore rockfill strata. Summary of the Invention

[0006] The purpose of this invention is to provide a method for drilling and backfilling the casing in near-shore rockfill sections, aiming to solve the problem of poor drilling and backfilling performance due to casing collapse during near-shore rockfill section construction in the prior art.

[0007] This invention is implemented as follows: a drilling method for backfilling collapsed sections of casing in near-shore rockfill sections, comprising the following construction steps: 1) A concrete slab is poured on the construction site to form a concrete slab, which covers the stone filling layer; 2) A rotary drilling rig is used to drill a pre-drilled section in the concrete slab, the pre-drilled section penetrating the concrete slab; 3) Insert the casing into the pre-drilled section, keeping the casing arranged longitudinally; 4) The rotary drilling rig drives the casing to rotate so that the casing penetrates into the rock filling layer. When the casing is lowered into the rock filling layer to a set depth, a void is formed between the concrete slab and the rock filling layer. The void is connected to the outer periphery of the casing. 5) Drill an outer peripheral hole in the concrete slab, the outer peripheral hole penetrating the concrete slab and connecting to the collapsed area, the outer peripheral plate being formed outside the casing; 6) Backfill the outer peripheral holes with outer peripheral clay, which fills the collapsed area and abuts against the outer periphery of the casing. The outer peripheral clay is formed by slurry filtration during on-site construction. Compact the outer peripheral clay so that it penetrates into the voids in the stone filling layer and presses against the outer periphery of the casing outward. 7) The stone filling layer has stones in holes located in the casing. Clay is backfilled into the stones in the holes. The clay in the holes is formed by filtration of mud generated during on-site construction. The clay in the holes is compacted so that it permeates into the gaps of the stones in the holes. 8) The punching hammer of the punching drill is used to punch holes in the casing. The punching hammer squeezes the clay in the hole into the gaps of the stone filling in the hole, and simultaneously breaks the stone filling in the hole until the punching hammer penetrates the stone filling layer to form a stone filling hole section.

[0008] Furthermore, in construction step 1), the construction site is leveled, debris is cleared from the construction site, and the construction site is compacted. The concrete slab is then poured into the compacted construction site.

[0009] Furthermore, in construction step 2), the bottom of the pre-drilled section extends into the rock-fill layer.

[0010] Furthermore, in construction step 3), after inserting the casing into the pre-drilled section, the casing is rotated back and forth so that the bottom of the casing passes through the bottom of the pre-drilled section and is embedded in the fill layer.

[0011] Furthermore, in construction step 4), after the casing is lowered into the stone filling layer to a set depth, the top of the casing extends above the concrete slab, and the bottom of the casing is located in the stone filling layer.

[0012] Furthermore, in construction step 5), a plurality of peripheral holes are drilled in the stone filling layer. The plurality of peripheral holes are arranged around the outer periphery of the casing and spaced apart from the casing. The plurality of peripheral holes are arranged in sequence to interlock so that adjacent peripheral holes are connected.

[0013] Furthermore, in construction step 8), during the process of the punching hammer punching holes in the casing, clay is continuously added into the casing until the punching hammer penetrates the stone filling layer. During the punching process in the casing, the stones in the hole are broken to form sediment, which settles at the bottom of the stone-filled hole section. Mud is injected into the bottom of the stone-filled hole section, and the mud in the hole swells upward and flows. The sediment overflows out of the stone-filled hole section with the flowing mud in the hole using a positive circulation slag discharge method.

[0014] Furthermore, in construction step 7), before backfilling the clay in the hole into the rock filling layer, the drill rod is used to drill longitudinally at the center of the rock filling layer to form a central hole. The central hole penetrates the rock filling layer and the bottom of the central hole extends into the soil layer to form the lower section. The central hole is filled with hole clay, the bottom of the hole clay fills the lower section, and the top of the hole clay covers the top of the hole fill. The hole clay is then compacted. During the compaction of the clay inside the hole, the clay at the top of the stone filling in the hole axially penetrates into the gaps of the stone filling in the hole, and the clay in the central hole axially penetrates into the gaps of the stone filling in the hole.

[0015] Furthermore, in construction step 6), the outer clay is compacted so that it penetrates into the gaps of the stone filling layer, and then an elastic element is inserted into the outer clay so that the interior of the outer clay is elastically compressed. The elastic element includes two oscillating plates arranged at opposite inclinations. The lower ends of the two oscillating plates are connected as one piece to form a pointed oscillating end. The upper ends of the two oscillating plates are separated from each other, and an oscillating interval is formed between the two oscillating plates. The oscillating plates are provided with multiple through holes. The upper ends of the oscillating plates are bent outward to form horizontally arranged pressing plates. The swing end is arranged downwards, the elastic element is inserted into the outer clay, the two swing plates are squeezed and swing elastically towards each other, the swing interval is reduced, and the pressing plate is horizontally pressed against the outer clay, so that the elastic element is fixed in the outer clay.

[0016] Furthermore, in the construction step 6), the pressing plate is provided with insertion holes arranged vertically and in a strip shape. When the elastic element is inserted into the outer clay and the pressing plate presses against the outer clay, a nail is inserted into the outer clay through the insertion hole. The diameter of the pin is smaller than the width of the hole, and the diameter of the pin is smaller than the length of the hole. The top of the pin has an end with a diameter larger than the width of the hole. The end presses against the pressure plate. The pin restricts the elastic deformation of the pressure plate along the width direction and positions the elastic deformation of the pressure plate along the length direction.

[0017] Compared with the prior art, the drilling method for backfilling the near-shore rock-filled section casing collapse provided by the present invention firstly involves pouring a concrete slab on the construction site to cover the rock-filled layer and then installing a casing. This reduces the initial disturbance of the rock-filled layer during the casing sinking process, suppresses the expansion of the collapse zone, and lays the foundation for subsequent backfilling work.

[0018] Subsequently, by backfilling the collapsed area, the surrounding clay formed by on-site pressure filtration is fully penetrated into the voids of the stone filling layer, making the stone filling layer more compact. This provides uniform lateral restraint force for the casing, preventing the casing from tilting or becoming unstable due to vibration during subsequent drilling operations, thus improving the stability of the casing.

[0019] Finally, stones are backfilled into the hole and the clay inside the hole is compacted. Combined with the squeezing action of the punching hammer, the clay fully penetrates into the gaps of the stones in the hole, further enhancing the integrity and strength of the stone filling layer.

[0020] At the same time, the squeezing action of the punching hammer simultaneously breaks up the local loose filling stone, reduces the interference of vibration on the collapsed area outside the casing, and avoids the further expansion of the collapsed area, thereby achieving a stable and efficient improvement in drilling construction results. Attached Figure Description

[0021] Figure 1 This is a schematic flowchart of the drilling method for backfilling and filling the near-shore rock-filled section casing collapse provided by the present invention; Figure 2 This is a simplified schematic diagram of the rotary drilling rig provided by the present invention. Figure 3 This is a simplified schematic diagram of the collapsed area around the casing provided by the present invention; Figure 4 This is a simplified schematic diagram of the peripheral hole provided by the present invention; Figure 5 This is a schematic diagram of the state of the collapsed area filled with clay on the periphery, provided by the present invention. Figure 6 This is a simplified schematic diagram of the punching hammer provided by the present invention punching holes in the casing; Figure 7 This is a cross-sectional schematic diagram of the protective sleeve and the outer peripheral hole provided by the present invention; Figure 8 This is a schematic diagram of the interior of the hole filled with stone provided by the present invention; Figure 9 This is a schematic cross-sectional view of the outer clay provided by the present invention; In the diagram: concrete slab 100, casing 101, rock fill layer 102, rock fill inside the hole 103, collapse zone 104, soil layer 105; Rotary drilling rig 200, pre-drilled section 201, outer peripheral hole 202, outer peripheral clay 203; 300 punching drill, 301 punching hammer, 302 hole drilling mud, 303 hole drilling clay; Center hole 400, lower section 401; Elastic element 500, swing plate 501, swing end 502, swing interval 503, through hole 504, pressing plate 505, insertion hole 506, insertion pin 507, end 508. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0023] The implementation of the present invention will be described in detail below with reference to specific embodiments.

[0024] In the accompanying drawings of this embodiment, the same or similar reference numerals correspond to the same or similar components. In the description of this invention, it should be understood that if terms such as "upper," "lower," "left," and "right" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, they are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the terms used to describe positional relationships in the drawings are only for illustrative purposes and should not be construed as limiting this invention. For those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.

[0025] Reference Figures 1-9 The image shown is a preferred embodiment of the present invention.

[0026] The drilling method for backfilling voids in the near-shore rockfill section includes the following construction steps: 1) A concrete slab 100 is poured on the construction site and the concrete slab 100 covers the stone filling layer 102. 2) A rotary drilling rig 200 is used to drill a pre-drilled section 201 in the concrete slab 100, and the pre-drilled section 201 penetrates the concrete slab 100. 3) Insert the casing 101 into the pre-drilled section 201, keeping the casing 101 arranged longitudinally; 4) The rotary drilling rig 200 drives the casing 101 to rotate so that the casing 101 penetrates into the rock filling layer 102. When the casing 101 is lowered into the rock filling layer 102 to a set depth, a void area 104 is formed between the concrete slab 100 and the rock filling layer 102. The void area 104 is connected to the outer periphery of the casing 101. 5) Drill an outer peripheral hole 202 in the concrete slab 100. The outer peripheral hole 202 penetrates the concrete slab 100 and connects to the collapsed area 104. The outer peripheral plate is formed on the outside of the casing 101. 6) Backfill the outer peripheral hole 202 with outer peripheral clay 203. The outer peripheral clay 203 fills the collapsed area 104 and abuts against the outer periphery of the casing 101. The outer peripheral clay 203 is formed by filtration of mud generated during on-site construction. Compact the outer peripheral clay 203 so that it can penetrate into the voids in the stone filling layer 102 and press against the outer periphery of the casing 101 outward. 7) The stone filling layer 102 has stone filling 103 in the hole located in the casing 101. Clay 303 is backfilled into the stone filling 103 in the hole. The clay 303 in the hole is formed by filtration of mud generated on site. The clay 303 in the hole is compacted so that the clay 303 in the hole can penetrate into the voids of the stone filling 103 in the hole. 8) Using the punching hammer 301 of the punching drill 300 to punch holes in the casing 101, the punching hammer 301 squeezes the clay 303 in the hole into the gap of the filling stone 103 in the hole, and simultaneously breaks the filling stone 103 in the hole until the punching hammer 301 penetrates the filling stone layer 102 to form a filling stone hole section.

[0027] The above-mentioned drilling method for backfilling the collapsed section of the near-shore rockfill section first involves pouring a concrete slab 100 on the construction site to cover the rockfill layer 102 and then constructing the casing 101. This reduces the initial disturbance of the rockfill layer 102 during the sinking process of the casing 101, suppresses the expansion of the collapsed area 104, and lays the foundation for subsequent backfilling work.

[0028] Subsequently, by backfilling the collapsed area 104, the outer clay 203 formed by on-site pressure filtration is fully penetrated into the voids of the stone filling layer 102, making the stone filling layer 102 more compact. This provides uniform lateral restraint force for the casing 101, preventing the casing 101 from tilting or becoming unstable due to vibration during subsequent drilling operations, thus improving the stability of the casing 101.

[0029] Finally, the stones 103 are backfilled into the hole and the clay 303 inside the hole is compacted. Combined with the squeezing action of the punching hammer 301, the clay fully penetrates into the gaps of the stones 103 inside the hole, further enhancing the integrity and strength of the stone filling layer 102.

[0030] At the same time, the squeezing action of the punching hammer 301 simultaneously breaks up the local loose filling stone, reduces the interference of vibration on the collapsed area 104 on the outside of the casing 101, and avoids the further expansion of the collapsed area 104, thereby achieving a stable and efficient improvement in drilling construction results.

[0031] In this embodiment, in construction step 1), the construction site is leveled, debris in the construction site is cleaned up, and the construction site is compacted. A concrete slab 100 is then poured into the compacted construction site.

[0032] This provides a stable and solid foundation for subsequent construction, ensuring the flatness and load-bearing capacity of the concrete slab 100, thereby guaranteeing the stability and safety of the entire construction process.

[0033] Especially in the rock-filled areas near the coast, the foundation is often relatively soft. By compacting the soil and pouring 100mm concrete slabs, problems such as uneven settlement can be prevented during subsequent construction, thus improving the construction quality.

[0034] In this embodiment, in construction step 2), the bottom of the pre-drilled section 201 extends into the rock-fill layer 102; This allows the pre-drilled section 201 to be better anchored within the rock fill layer 102, providing stable guidance and support for the subsequent installation and drilling of the casing 101.

[0035] In actual construction, the stability of the rock filling layer 102 is crucial to the bearing capacity of the entire foundation. The bottom of the pre-drilled section 201 extends into the rock filling layer 102, which helps to enhance the stability of the pile foundation, reduce the risk of hole collapse during construction, and improve construction efficiency and pile quality.

[0036] In this embodiment, in construction step 3), after inserting the casing 101 into the pre-drilled section 201, the casing 101 is rotated back and forth so that the bottom of the casing 101 passes through the bottom of the pre-drilled section 201 and is embedded in the stone filling layer 102.

[0037] By reciprocating the rotation of the casing 101, the bottom of the casing 101 is more firmly embedded in the rock filling layer 102, enhancing the stability and sealing of the casing 101. During the drilling process, the stability and sealing of the casing 101 are of great significance for preventing borehole collapse, ensuring the verticality of the borehole, and ensuring smooth drilling operations, which can effectively improve the construction results.

[0038] In this embodiment, in construction step 4), after the casing 101 is lowered into the stone filling layer 102 to a set depth, the top of the casing 101 extends above the concrete slab 100, and the bottom of the casing 101 is located in the stone filling layer 102.

[0039] This allows the casing 101 to be isolated from the concrete slab 100, accurately guiding the subsequent construction of the rock filling layer 102. At the same time, the top of the casing 101 extends above the concrete slab 100, facilitating subsequent drilling operations and the fixing and adjustment of the casing 101, thus improving the convenience and flexibility of construction.

[0040] In this embodiment, in construction step 5), multiple peripheral holes 202 are drilled in the stone filling layer 102. The multiple peripheral holes 202 are arranged around the outer periphery of the casing 101 and are spaced apart from the casing 101. The multiple peripheral holes 202 are arranged in sequence to interlock so that adjacent peripheral holes 202 are connected.

[0041] Through the interlocking of multiple peripheral holes 202, a relatively complete backfill area can be formed around the outer periphery of the casing 101, so that the peripheral clay 203 can be evenly filled into the collapsed area 104 and tightly bonded to the stone filling layer 102.

[0042] In actual construction, this arrangement helps to improve the compactness and uniformity of backfill, and enhance the stability and bearing capacity of the outer periphery of the casing 101. Moreover, when encountering situations such as a large diameter of the casing 101 or a high porosity of the rock filling layer 102, the number and depth of the outer periphery holes 202 can be appropriately increased to ensure the integrity and effectiveness of the clay curtain, thereby making the drilling construction for backfilling around the casing 101 more effective.

[0043] In this embodiment, during construction step 8), as the punching hammer 301 punches a hole in the casing 101, clay 303 is continuously added into the casing 101 until the punching hammer 301 penetrates the stone filling layer 102. During the punching process of the punching hammer 301 in the casing 101, the stones 103 in the hole are broken into sediment, which settles at the bottom of the stone-filled hole section. The mud 302 in the hole is injected into the bottom of the stone-filled hole section. The mud 302 in the hole rises and flows. The sediment overflows out of the stone-filled hole section with the flowing mud 302 in the hole using a positive circulation slag discharge method.

[0044] By rationally configuring the positive circulation slag removal method, the sediment in the hole can be discharged, keeping the hole clean. At the same time, the continuous addition of clay 303 and the circulation of mud 302 in the hole help stabilize the hole wall, prevent hole wall collapse, and improve drilling efficiency and hole quality.

[0045] The positive circulation slag removal method mentioned in this embodiment can be achieved by pumping the mud 302 into the drill pipe cavity through a mud pump, carrying the slag back out through the annular space between the drill pipe and the hole wall. This can continuously clean the slag at the bottom of the hole, keep the bottom of the hole clean, facilitate the efficient operation of the punching hammer 301, and reduce the risk of drill bit wear and stuck drill due to slag accumulation.

[0046] In this embodiment, in construction step 7), before backfilling the clay 303 into the hole filling stone 103, the drill rod is used to drill longitudinally at the center of the hole filling stone 103 to form a central hole 400. The central hole 400 penetrates the stone filling layer 102, and the bottom of the central hole 400 extends into the soil layer 105 to form the lower section 401. The central hole 400 is filled with hole clay 303. The bottom of the hole clay 303 fills the lower section 401, and the top of the hole clay 303 covers the top of the hole fill. The hole clay 303 is then compacted. During the compaction process of the clay 303 inside the hole, the clay 303 at the top of the stone filling 103 inside the hole axially penetrates into the voids of the stone filling 103 inside the hole, and the clay 303 inside the central hole 400 also axially penetrates into the voids of the stone filling 103 inside the hole.

[0047] By pre-forming a central hole 400 and filling it with clay 303 in the stone filling 103, the clay can be guided to spread outwards and fill the pores of the stone filling during the subsequent drilling hammer 301 operation. This makes the clay 303 more evenly distributed throughout the stone filling 103 area, enhancing the integrity and density of the stone filling layer 102, improving the bearing capacity of the pile foundation, and preventing the stone filling 103 from loosening and settling during subsequent use.

[0048] For example, when dealing with fill layers 102 with high porosity or uneven particle size of fill stones 103, the central hole 400 can improve the filling efficiency of clay 303 in the hole, reduce unfilled areas, enhance the integrity of fill layer 102, reduce the risk of grout leakage during subsequent concrete pouring, and improve the integrity of the pile body.

[0049] In this embodiment, in construction step 6), the outer clay 203 is compacted so that it penetrates into the gaps of the stone filling layer 102. Then, an elastic element 500 is inserted into the outer clay 203 so that the interior of the outer clay 203 is elastically compressed. The elastic element 500 includes two oscillating pieces 501 arranged at opposite inclinations. The lower ends of the two oscillating pieces 501 are connected as one piece to form a pointed oscillating end 502. The upper ends of the two oscillating pieces 501 are separated from each other, and an oscillating interval 503 is formed between the two oscillating pieces 501. Multiple through holes 504 are provided in the oscillating pieces 501. The upper ends of the oscillating pieces 501 are bent outward to form a horizontally arranged pressing piece 505. The swing end 502 is arranged downwards, the elastic element 500 is inserted into the outer clay 203, the two swing pieces 501 are squeezed and swing elastically towards each other, the swing interval 503 is reduced, and the pressing piece 505 is horizontally pressed against the outer clay 203 so that the elastic element 500 is fixed in the outer clay 203.

[0050] Through the elastic compression of the elastic element 500, the outer clay 203 forms a denser filling in the pores of the stone filling layer 102. At the same time, the elastic element 500 itself also acts as a skeleton, enabling the outer clay 203 to better support and constrain the outer periphery of the casing 101, thereby improving the stability and construction effect of the casing 101.

[0051] In this embodiment, in construction step 6), the pressing plate 505 is provided with an insertion hole 506 arranged vertically and horizontally in a strip shape. When the elastic element 500 is inserted into the outer clay 203 and the pressing plate 505 presses against the outer clay 203, the pin 507 is inserted into the outer clay 203 through the insertion hole 506. The diameter of the pin 507 is smaller than the width of the hole 506, and the diameter of the pin 507 is smaller than the length of the hole 506. The top of the pin 507 has an end 508, the diameter of which is larger than the width of the hole 506. The end 508 presses against the pressing plate 505. The pin 507 restricts the elastic deformation of the pressing plate 505 along the width direction and positions the elastic deformation of the pressing plate 505 along the length direction. In this way, the deformation of the elastic element 500 during the stress process can be restricted, ensuring that its squeezing effect on the outer clay 203 is more stable and uniform.

[0052] In practical applications, the setting of the pin 507 enables the elastic element 500 to elastically deform in a predetermined direction and manner. This deformation control allows the elastic element 500 to continuously and stably apply pressure to the outer clay 203, further enhancing the density and stability of the outer clay 203.

[0053] Meanwhile, the end cap 508 can prevent the insert pin 507 from being pulled out when under stress, ensuring the long-term stability and reliability of the entire structure, providing more solid support and constraint for the casing 101, and improving the stability and construction effect of the casing 101.

[0054] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A drilling method for backfilling and drilling in near-shore rock-filled sections where the casing collapses, characterized in that... The construction steps include the following: 1) A concrete slab is poured on the construction site to form a concrete slab, which covers the stone filling layer; 2) A rotary drilling rig is used to drill a pre-drilled section in the concrete slab, the pre-drilled section penetrating the concrete slab; 3) Insert the casing into the pre-drilled section, keeping the casing arranged longitudinally; 4) The rotary drilling rig drives the casing to rotate so that the casing penetrates into the rock filling layer. When the casing is lowered into the rock filling layer to a set depth, a void is formed between the concrete slab and the rock filling layer. The void is connected to the outer periphery of the casing. 5) Drill an outer peripheral hole in the concrete slab, the outer peripheral hole penetrating the concrete slab and connecting to the collapsed area, the outer peripheral plate being formed outside the casing; 6) Backfill the outer peripheral holes with outer peripheral clay, which fills the collapsed area and abuts against the outer periphery of the casing. The outer peripheral clay is formed by slurry filtration during on-site construction. Compact the outer peripheral clay so that it penetrates into the voids in the stone filling layer and presses against the outer periphery of the casing outward. 7) The stone filling layer has stones in holes located in the casing. Clay is backfilled into the stones in the holes. The clay in the holes is formed by filtration of mud generated during on-site construction. The clay in the holes is compacted so that it permeates into the gaps of the stones in the holes. 8) The punching hammer of the punching drill is used to punch holes in the casing. The punching hammer squeezes the clay in the hole into the gaps of the stone filling in the hole, and simultaneously breaks the stone filling in the hole until the punching hammer penetrates the stone filling layer to form a stone filling hole section.

2. The drilling method for backfilling and drilling in the near-shore rock-fill section where the casing collapses, as described in claim 1, is characterized in that... In construction step 1), the construction site is leveled, debris is cleared from the construction site, and the construction site is compacted. The concrete slab is then poured into the compacted construction site.

3. The drilling method for backfilling and drilling in the near-shore rock-fill section where the casing collapses, as described in claim 1, is characterized in that... In construction step 2), the bottom of the pre-drilled section extends into the rock-fill layer.

4. The drilling method for backfilling and drilling in the near-shore rock-fill section where the casing collapses, as described in claim 1, is characterized in that... In construction step 3), after inserting the casing into the pre-drilled section, the casing is rotated back and forth so that the bottom of the casing passes through the bottom of the pre-drilled section and is embedded in the stone filling layer.

5. The drilling method for backfilling and drilling in the near-shore rock-fill section where the casing collapses, as described in claim 1, is characterized in that... In construction step 4), after the casing is lowered to a set depth in the stone filling layer, the top of the casing extends above the concrete slab, and the bottom of the casing is located in the stone filling layer.

6. The drilling method for backfilling and drilling in the near-shore rock-fill section where the casing collapses, as described in claim 1, is characterized in that... In construction step 5), multiple peripheral holes are drilled in the stone filling layer. The multiple peripheral holes are arranged around the outer periphery of the casing and spaced apart from the casing. The multiple peripheral holes are arranged in sequence to interlock so that adjacent peripheral holes are connected.

7. The drilling method for backfilling and drilling in the near-shore rock-fill section where the casing collapses, as described in claim 1, is characterized in that... In construction step 8), during the process of the punching hammer punching a hole in the casing, clay is continuously added into the casing until the punching hammer penetrates the stone filling layer. During the punching process in the casing, the stones in the hole are broken to form sediment, which settles at the bottom of the stone-filled hole section. Mud is injected into the bottom of the stone-filled hole section, and the mud in the hole swells upward and flows. The sediment overflows out of the stone-filled hole section with the flowing mud in the hole using a positive circulation slag discharge method.

8. The drilling method for backfilling and drilling in the near-shore rock-fill section where the casing collapses, as described in claim 1, is characterized in that... In construction step 7), before backfilling the clay in the hole into the rock filling layer, the drill rod is used to drill longitudinally at the center of the rock filling layer to form a central hole. The central hole penetrates the rock filling layer and the bottom of the central hole extends into the soil layer to form the lower section. The central hole is filled with hole clay, the bottom of the hole clay fills the lower section, and the top of the hole clay covers the top of the hole fill. The hole clay is then compacted. During the compaction of the clay inside the hole, the clay at the top of the stone filling in the hole axially penetrates into the gaps of the stone filling in the hole, and the clay in the central hole axially penetrates into the gaps of the stone filling in the hole.

9. The drilling method for backfilling and drilling in the near-shore rock-fill section where the casing collapses, as described in any one of claims 1-8, is characterized in that... In construction step 6), the outer clay is compacted so that it penetrates into the gaps of the stone filling layer. Then, an elastic element is inserted into the outer clay so that the interior of the outer clay is elastically compressed. The elastic element includes two oscillating plates arranged at opposite inclinations. The lower ends of the two oscillating plates are connected as one piece to form a pointed oscillating end. The upper ends of the two oscillating plates are separated from each other, and an oscillating interval is formed between the two oscillating plates. The oscillating plates are provided with multiple through holes. The upper ends of the oscillating plates are bent outward to form horizontally arranged pressing plates. The swing end is arranged downwards, the elastic element is inserted into the outer clay, the two swing plates are squeezed and swing elastically towards each other, the swing interval is reduced, and the pressing plate is horizontally pressed against the outer clay, so that the elastic element is fixed in the outer clay.

10. The drilling method for backfilling and drilling in the near-shore rock-fill section where the casing collapses, as described in claim 9, is characterized in that... In construction step 6), the pressing plate is provided with insertion holes arranged vertically and in a strip shape. When the elastic element is inserted into the outer clay and the pressing plate presses against the outer clay, a nail is inserted into the outer clay through the insertion hole. The diameter of the pin is smaller than the width of the hole, and the diameter of the pin is smaller than the length of the hole. The top of the pin has an end with a diameter larger than the width of the hole. The end presses against the pressure plate. The pin restricts the elastic deformation of the pressure plate along the width direction and positions the elastic deformation of the pressure plate along the length direction.

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