Hard inclined rock face cast-in-place pile drilling method

Abstract

The application provides a hard inclined rock surface cast-in-place pile drilling method and relates to the technical field of building engineering. The hard inclined rock surface cast-in-place pile drilling method comprises the following steps: determining the position of the soft rock layer of the pile hole; inserting the first excess steel bars of the pile foundation reinforcement cage main reinforcement into the soft rock layer along the axial direction of the pile hole and backfilling the first layer of stone slices; pressing the first excess steel bars and the first layer of stone slices into the soft rock layer by using an impact drill; making the second excess steel bars of the pile foundation reinforcement cage main reinforcement into a steel mesh and horizontally filling the steel mesh into the pile hole; backfilling the second layer of stone slices on the steel mesh; impacting the second layer of stone slices by using the impact drill; and drilling. The combined backfilling of the horizontal steel mesh and the second layer of stone slices can improve the uniformity of the impact interface, avoid the deflection of the drilling tool of the impact drill, and thus can reduce the drilling cost of the hard inclined rock surface cast-in-place pile and improve the drilling construction efficiency.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of building engineering, in particular to a method for drilling a cast-in-place pile on a hard inclined rock surface. BACKGROUND

[0002] In a hard inclined rock surface, a cast-in-place pile on an inclined rock area can be divided into a soft rock layer with a smaller bearing capacity and a hard rock layer with a larger bearing capacity due to the different bearing capacities of the geology on both sides of the hole bottom. In the drilling process, accidents such as inclined pile, hole expansion, drill burying, and even pile breaking are easily caused.

[0003] At present, the main method for processing the drilling of a pile foundation on an inclined rock surface is to use backfilling of high-strength stone pieces, pouring of early-strength concrete, or underwater blasting to process the inclined rock surface, and then to perform drilling construction by using an impact drill. The conventional high-strength stone piece method or the early-strength concrete method has a long construction period and low work efficiency, and the procurement cost of the high-strength stone pieces is relatively high. In particular, in areas such as karst areas that lack high-strength stone materials, the procurement of high-strength stone pieces will significantly increase the construction cost. SUMMARY

[0004] The present application solves the problem of how to balance the construction cost and the drilling construction efficiency on an inclined hard rock surface.

[0005] To solve the above problem, the present application provides a method for drilling a cast-in-place pile on a hard inclined rock surface, comprising:

[0006] determining the position of a soft rock layer of a pile hole;

[0007] inserting a first excess steel bar of a pile foundation reinforcement cage main reinforcement along the axial direction of the pile hole into the soft rock layer and backfilling a first layer of stone pieces;

[0008] pressing the first excess steel bar and the first layer of stone pieces into the soft rock layer by using an impact drill;

[0009] manufacturing a second excess steel bar of the pile foundation reinforcement cage main reinforcement into a steel mesh and horizontally filling the steel mesh into the pile hole;

[0010] backfilling a second layer of stone pieces on the steel mesh;

[0011] impacting the second layer of stone pieces by using the impact drill;

[0012] drilling a hole.

[0013] Optionally, the thickness of the first layer of stone pieces is KDtanθ / 2, wherein D is the diameter of the pile hole, θ is the angle of the inclined rock surface, and K is the compaction degree of the soft rock layer.

[0014] Optionally, the method further comprises detecting the hole depth periodically during the impact drilling, and stopping the impact drilling when the difference between the hole bottom elevation and the highest point of the inclined rock surface is 0.3-0.5 m.

[0015] Optionally, the method further comprises that the mud specific gravity is 1.2-1.4 during the impact drilling.

[0016] Optionally, the distance between two adjacent steel bars is 0.15-0.3 m, and the diameter of the steel bar mesh is 10 cm smaller than the diameter of the pile hole.

[0017] Optionally, the method further comprises that the number of layers of the steel bar mesh near the hard rock layer is one, and the number of layers of the steel bar mesh near the soft rock layer is multiple.

[0018] Optionally, the thickness of the second layer of rock pieces is 0.3-0.5 m, and the diameter of the rock pieces is 0.5-0.8 m.

[0019] Optionally, the method further comprises that the stroke of the impact drill is 0.5-1 m when the impact drill impacts the second layer of rock pieces in step three.

[0020] Optionally, the method further comprises that:

[0021] If the drill slag contains steel slag, the impact is stopped.

[0022] The number of layers of the steel bar mesh is increased, and the second layer of rock pieces is backfilled before impact drilling.

[0023] Optionally, the method further comprises that when the pile foundation drilling reaches the inclined hard rock surface, and the steel wire rope of the impact drill swings or an abnormal sound occurs during the punching process, the drilling is stopped.

[0024] Compared with the related art, the hard inclined rock surface cast-in-place pile drilling method can press the first excess steel bar and the first layer of stone into the soft rock layer by using the impact drill after determining the position of the soft rock layer in the pile hole in the hard inclined rock surface cast-in-place pile drilling construction process, so as to improve the structural strength of the soft rock layer by using the structural strength of the first excess steel bar together with the first layer of stone, and the combined backfill of the first excess steel bar and the first layer of stone can save the construction time of the cast-in-place early strength concrete, thereby reducing the drilling time, and the first excess steel bar is the excess of the pile foundation reinforcement cage main reinforcement, which is simple to obtain and can realize secondary utilization of the excess of the pile foundation reinforcement cage main reinforcement, thereby reducing the use cost of the first excess steel bar, avoiding the purchase of high-strength stone to some extent, reducing the purchase cost of the high-strength stone, further reducing the cost of the hard inclined rock surface cast-in-place pile drilling, and then the second excess steel bar of the pile foundation reinforcement cage main reinforcement is made into a steel mesh, the steel mesh is filled horizontally into the pile hole, the second layer of stone is backfilled on the steel mesh, the impact drill impacts the second layer of stone, further realizes the secondary utilization of the excess of the pile foundation reinforcement cage main reinforcement, and the combined backfill of the horizontal steel mesh and the second layer of stone can improve the uniformity of the impact interface and avoid the deflection of the drilling tool of the impact drill, so as to reduce the cost of the hard inclined rock surface cast-in-place pile drilling while improving the drilling construction efficiency. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 The flowchart of the hard inclined rock surface cast-in-place pile drilling method in the embodiment of the present application is shown in the figure.

[0026] Figure 2 The distribution of the hard rock layer and the soft rock layer in the pile hole in the embodiment of the present application is shown in the figure.

[0027] Figure 3 The backfilling of the first layer of stone in the embodiment of the present application is shown in the figure.

[0028] Figure 4 The figure shows when the hole bottom elevation is 0.3-0.5 m higher than the elevation of the highest point of the hard rock layer.

[0029] Figure 5 The arrangement of the steel mesh in the embodiment of the present application is shown in the figure.

[0030] Figure 6 The arrangement of the backfilled steel mesh and the impact drilling in the embodiment of the present application is shown in the figure.

[0031] Figure 7 The drilling process in the embodiment of the present application is shown in the figure. Figure 1

[0032] Figure 8 The drilling process in the embodiment of the present application is shown in the figure. Figure 2 ​​

[0033] Figure 9 Schematic diagram of the drilling process in the embodiment of the present application Figure 2 .

[0034] Reference numerals:

[0035] 1 - pile hole; 2 - hard rock stratum; 3 - weak rock stratum; 4 - rock surface boundary; 5 - first excess reinforcement; 6 - reinforcement mesh; 7 - first layer of stone; 8 - second layer of stone. DETAILED DESCRIPTION

[0036] In order to make the above objectives, characteristics and advantages of the present application more apparent, comprehensible and easier to understand, the specific embodiments of the present application will be described in detail below with reference to the accompanying drawings.

[0037] In the drawings, the X axis represents the horizontal position, and the positive direction of the X axis (that is, the direction in which the arrow of the X axis points) represents the right side, and the negative direction of the X axis (that is, the direction opposite to the positive direction of the X axis) represents the left side; the Z axis represents the vertical position, and the positive direction of the Z axis (that is, the direction in which the arrow of the Z axis points) represents the upper side, and the negative direction of the Z axis (that is, the direction opposite to the positive direction of the Z axis) represents the lower side. It should be noted that the above-mentioned meanings of the Z axis and the X axis are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application.

[0038] It should be noted that the terms "first", "second", and the like in the specification and claims of the present application and the above drawings are used to distinguish similar objects, and do not necessarily have to be used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged under appropriate circumstances, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein.

[0039] In hard inclined rock surfaces, inclined rock area bored piles can be divided into weak rock stratum with smaller bearing capacity and hard rock stratum with larger bearing capacity due to the different bearing capacities of the geology on both sides of the hole bottom. In the drilling process, accidents such as inclined piles, hole expansion, drill burying, and even pile breaking are easily caused.

[0040] Currently, the drilling treatment method of the inclined rock surface pile foundation mainly adopts backfilling high-strength sheet stone, pouring early-strength concrete or underwater blasting method for treatment, and then impact drilling is conducted for drilling construction. The treatment period of the conventional high-strength sheet stone or pouring early-strength concrete method is long, the work efficiency is low, and the procurement cost of the high-strength sheet stone is relatively high, especially in the karst area and other areas lacking high-strength sheet stone, the procurement of the high-strength sheet stone will significantly increase the construction cost. The underwater blasting treatment has high safety risk. The use of the down-the-hole drill + impact drill treatment needs to increase the down-the-hole drill equipment and the steel casing pipe, and for the engineering in which only a few pile foundations are located in the inclined hard rock surface, the cost is high, and the process is relatively complex. Based on the above problems, the embodiment of the present application provides a hard inclined rock surface cast-in-place pile drilling method, which is suitable for the karst area and other areas lacking high-strength sheet stone, and the steel reinforcement net sheet is made from the steel reinforcement surplus of the pile foundation reinforcement cage, the steel reinforcement, the steel reinforcement net sheet and the sheet stone are backfilled into the pile hole, the uniformity of the stress of the impact interface is ensured, the inclined rock surface pile foundation drilling deflection problem can be quickly solved, and the efficiency of the inclined rock surface drilling construction is improved.

[0041] In combination with Figures 1 to 9 The present application provides a hard inclined rock surface cast-in-place pile drilling method, which comprises:

[0042] Step one: determining the position of the soft rock layer 3 of the pile hole 1;

[0043] Step two: inserting the first surplus steel reinforcement 5 of the pile foundation reinforcement cage main reinforcement along the axial direction of the pile hole 1 into the soft rock layer 3 and backfilling the first layer of sheet stone 7;

[0044] Step three: pressing the first surplus steel reinforcement 5 and the first layer of sheet stone 7 into the soft rock layer 3 by using the impact drill;

[0045] Step four: making the second surplus steel reinforcement of the pile foundation reinforcement cage main reinforcement into a steel reinforcement net sheet 6 and horizontally filling the steel reinforcement net sheet 6 into the pile hole 1;

[0046] Step five: backfilling the second layer of sheet stone 8 on the steel reinforcement net sheet 6;

[0047] Step six: impacting the second layer of sheet stone 8 by using the impact drill;

[0048] Step seven: drilling.

[0049] Specifically, in the pile hole 1, the position where the hard rock layer 2 contacts the soft rock layer 3 is the rock surface boundary line 4, as shown in the figure. Figure 2 As shown in the figure, the soft rock layer 3 is located above the rock surface boundary line 4, and the hard rock layer 2 is located below the rock surface boundary line 4. As shown in the figure, Figure 2As shown, when it is found that the drill hole has drilled to the inclined hard rock surface, and it is determined that the soft rock layer 3 is located above the left of the hard rock layer 2, the drill tool is withdrawn from the pile hole 1, and the remaining part of the steel bar after the completion of the pile steel cage main reinforcement is used to make the first excess steel bar 5, and the remaining part is the second excess steel bar. As shown Figure 3 As shown, the first excess steel bar 5 is inserted into the soft rock layer 3 along the axis of the pile hole 1, and the first layer of stone 7 is backfilled on the first excess steel bar, after the backfilling of the first layer of stone 7, the first layer of stone 7 is impacted by the percussion drill, and the process of impacting the first layer of stone 7 by the percussion drill can press the first layer of stone 7 into the soft rock layer 3, and also press the first excess steel bar into the soft rock layer 3, as shown Figure 4 As shown, so that the first excess steel bar 5 and the first layer of stone 7 are distributed in the soft rock layer 3, and the rigidity of the first excess steel bar 5 and the first layer of stone 7 is used to improve the structural strength of the soft rock layer 3, as shown Figure 5 and Figure 6 At the construction site, the second excess steel bar is used to make the steel mesh 6, which is filled horizontally into the pile hole 1, and then the second layer of stone 8 is backfilled on the horizontal steel mesh 6, and the percussion drill impacting the second layer of stone 8 under the support of the horizontal steel mesh 6 can make the filling plane of the second layer of stone 8 in the pile hole 1 also horizontal, as shown Figures 7 to 9 As shown, the drill hole is drilled until the inclined hard rock layer 2 is constructed horizontally. In the process of drilling, the bearing capacity of the soft rock layer 3 is improved by the first excess steel bar and the first layer of stone 7, and the horizontal steel mesh 6 makes the stress of the second layer of stone 8 more uniform, avoiding the inclination of the drill tool of the percussion drill due to the filling of the second layer of stone 8, so as to not only improve the structural strength of the soft rock layer 3, but also solve the problem of pile hole deflection of the inclined rock surface, thereby improving the efficiency of the hard inclined rock surface bored pile drilling. In addition, the excess material remaining after the completion of the pile steel cage main reinforcement at the construction site is used in the embodiment, which can reduce the amount of high-strength stone, and does not need to be treated by early strength concrete or underwater blasting method, so as to reduce the cost of the hard inclined rock surface bored pile hole.

[0050] Therefore, in the embodiment, in the drilling construction process of the cast-in-place pile on the hard inclined rock surface, and after the position of the soft rock layer 3 of the pile hole 1 is determined, the first excess steel bars 5 and the first layer of stones 7 can be pressed into the soft rock layer 3 by the percussion drill, so that the structural strength of the first excess steel bars 5 is used to improve the structural strength of the soft rock layer 3 together with the first layer of stones 7, and the combined backfill of the first excess steel bars 5 and the first layer of stones 7 can save the construction time of the cast-in-place early strength concrete, thereby reducing the drilling time. The first excess steel bars 5 are the excess of the main reinforcement of the pile cage, which is easy to obtain and can realize the secondary use of the excess of the main reinforcement of the pile cage, thereby reducing the use cost of the first excess steel bars 5. To some extent, the purchase of high-strength stones can be avoided to reduce the purchase cost of the high-strength stones, thereby further reducing the cost of the drilling of the cast-in-place pile on the hard inclined rock surface. Then, the second excess steel bars of the main reinforcement of the pile cage are made into the steel mesh 6, and the steel mesh 6 is filled horizontally into the pile hole 1. The second layer of stones 8 is backfilled on the steel mesh 6, and the second layer of stones 8 is impacted by the percussion drill, thereby further realizing the secondary use of the excess of the main reinforcement of the pile cage. At the same time, the combined backfill of the horizontal steel mesh 6 and the second layer of stones 8 can improve the uniformity of the impact interface and avoid the deflection of the drilling tool of the percussion drill, thereby improving the drilling construction efficiency while reducing the cost of the drilling of the cast-in-place pile on the hard inclined rock surface.

[0051] Optionally, in combination with Figure 5 As shown in the figure, the thickness of the first layer of stones 7 is KDtanθ / 2, wherein D is the diameter of the pile hole 1, θ is the angle of the inclined rock surface, and K is the density of the soft rock layer 3. θ and K can be obtained according to the geological survey report.

[0052] Specifically, K is the density of the soft rock layer 3, and the value range is generally between 1 and 2. During drilling, the thickness of the first layer of backfill stones can be 1.2 x 2 x tan45° / 2 = 1.2 m, wherein the block diameter of the first layer of backfill stones is between 0.8 and 1.2 m. Considering that the first layer of stones 7 needs to be pressed into the soft rock layer 3, if the thickness of the first layer of stones 7 pressed into the soft rock layer 3 is too thick, the use of the first layer of stones 7 will be excessive, and the cost will be high. If the thickness of the first layer of stones 7 pressed into the soft rock layer 3 is too thin, the first layer of stones 7 cannot improve the bearing strength of the soft rock layer 3 together with the first excess steel bars 5. During the backfilling of the first layer of backfill stones, the block diameter of the first backfill stone is relatively large, and the block diameter of the later backfill stone is relatively small, thereby further reducing the use cost of the stones. After the first backfilling, the stroke of the drill bit of the percussion drill is relatively large, so that the first excess steel bars 5 can be inserted into the soft rock layer 3 by using the stones with a relatively large block diameter.

[0053] Thus, the thickness of the first layer of stones 7 can be calculated by the thickness KDtanθ / 2, where D is the diameter of the pile hole 1, θ is the angle of the inclined rock surface, and K is the density of the soft rock layer 3. The thickness of the first layer of stones 7 is moderate to ensure that the impact of the impact drill can completely press the backfilled first layer of stones 7 into the soft rock layer 3 after filling the first layer of stones 7, thereby ensuring that the first layer of stones 7 can effectively improve the bearing capacity of the soft rock layer 3.

[0054] Optionally, as shown in Figure 4 the hard inclined rock surface cast-in-place pile drilling method further comprises: during the impact drilling process, periodically detecting the hole depth, and stopping the impact when the difference between the hole bottom elevation and the elevation of the highest point of the inclined rock surface is in the range of 0.3-0.5 m.

[0055] Specifically, the hole bottom elevation refers to the vertical distance between the hole bottom or the first layer of stones 7 and the top end of the pile hole 1. The elevation of the highest point of the inclined rock surface refers to the vertical distance between the highest position of the inclined hard rock surface and the top end of the pile hole 1. When the difference between the hole bottom elevation and the elevation of the highest point of the inclined rock surface is in the range of 0.3-0.5 m, the impact is stopped.

[0056] Thus, during the impact drilling process, the hole depth is periodically detected, and the impact is stopped when the difference between the hole bottom elevation and the elevation of the highest point of the inclined rock surface is in the range of 0.3-0.5 m. At this time, the hole bottom is 0.3-0.5 m away from the highest point of the inclined rock surface, which can avoid repeated impact of the impact drill on the hard inclined rock surface, causing the inclined hole or the expansion hole to be buried, thereby improving the efficiency of the drilling construction. Meanwhile, the difference between the hole bottom elevation and the elevation of the highest point of the inclined rock surface being in the range of 0.3-0.5 m can avoid the backfill thickness of the first layer of stones 7 being too thick, which prolongs the time of impact drilling, affecting the drilling efficiency. Meanwhile, it also avoids the backfill thickness of the first layer of stones 7 being too thin, which reduces the backfill times of the first layer of stones 7, thereby improving the construction efficiency.

[0057] Optionally, the hard inclined rock surface cast-in-place pile drilling method further comprises: during the impact drilling process, the mud specific gravity is in the range of 1.2-1.4.

[0058] Specifically, during the impact drilling process, the mud can maintain the stability of the pile hole. If the mud specific gravity is less than 1.2 during the drilling process, the mud cake formed during the drilling process is too thin, the hole strength is low, and the drilling efficiency is affected. If the mud specific gravity is greater than 1.4 during the drilling process, the mud cake formed during the drilling process is too thick, which increases the load of the drilling tool and affects the drilling efficiency.

[0059] Thus, in the process of impact drilling, the mud specific gravity is in the range of 1.2-1.4, which ensures the stability of the hole wall in the drilling process and ensures that the mud cake formed in the drilling process is neither too thick nor too thin, thereby improving the drilling efficiency.

[0060] Optionally, in combination with Figure 5 As shown in the figure, the spacing d between the adjacent two steels of the steel mesh 6 is in the range of 0.15-0.3 m, and the diameter of the steel mesh 6 is 10 cm smaller than the diameter of the pile hole 1.

[0061] Thus, the spacing d between the adjacent two steels of the steel mesh 6 is in the range of 0.15-0.3 m, so that the structure of the steel mesh 6 is relatively compact, which can ensure that the structure of the steel mesh 6 is more secure under stress. The size of the steel mesh 6 is 10 cm smaller than the diameter of the pile hole 1, which can avoid the end of the steel colliding with the mud cake of the hole wall during the process of lowering the steel mesh 6 into the pile hole 1, thereby preventing slurry leakage.

[0062] In some embodiments, the thickness of the steel mesh 6 backfill is in the range of 0.3-0.5 m, which can avoid repeated impact on the hard inclined rock surface to cause inclined hole or expansion hole drilling, thereby ensuring the drilling quality and improving the efficiency of drilling construction.

[0063] Optionally, as Figure 5 As shown in the figure, the number of layers of the steel mesh 6 near the hard rock layer 2 is one layer, and the number of layers of the steel mesh 6 near the soft rock layer 3 is multiple layers.

[0064] Specifically, Figure 5 In the figure, a represents the side near the soft rock layer 3, and b represents the side near the hard rock layer 2. Only one layer of steel mesh 6 is arranged on the side of the hard rock layer 2, and two layers of steel mesh 6 are arranged on the side of the soft rock layer 3, in order to balance the strength of the side of the hard rock layer 2 and the strength of the side of the soft rock layer 3, and fully ensure the uniformity of the bearing capacity of the impact interface.

[0065] Thus, the number of layers of the steel mesh 6 near the hard rock layer 2 is one layer, and the number of layers of the steel mesh 6 near the soft rock layer 3 is multiple layers, which fully ensures the uniformity of the bearing capacity of the impact interface.

[0066] Optionally, the thickness of the stone sheet 8 is in the range of 0.3-0.5 m, and the diameter of the stone block is in the range of 0.5-0.8 m.

[0067] Therefore, the thickness of the second layer of stone pieces 8 is 0.3-0.5 m, so as to avoid that the backfilling thickness of the second layer of stone pieces 8 is too thick, the impact drill takes too long time to punch a hole, and the drilling efficiency is affected, and meanwhile, the backfilling thickness of the second layer of stone pieces 8 is too thin to fully utilize the strength of the steel bars, the backfilling times of the second layer of stone pieces 8 are reduced, and the construction efficiency is improved. The size of the stone pieces is 0.5-0.8 m, so as to reduce the purchase cost of the stone pieces.

[0068] Optionally, the method further comprises that, when the impact drill impacts the second layer of stone pieces 8, the stroke of the impact drill is 0.5-1 m.

[0069] Specifically, the stroke of the impact drill refers to the distance that the drill bit moves back and forth in the drill rod when the impact drill is working.

[0070] Therefore, when the impact drill impacts the second layer of stone pieces 8, the stroke of the impact drill is 0.5-1 m, so as to make the stroke of the impact drill small, and avoid that the impact force is too large to cause the bending of the steel bar mesh 6.

[0071] Optionally, the method further comprises:

[0072] If the slag sample of the hole contains the slag sample of the steel bar 6, the impact is stopped.

[0073] The number of layers of the steel bar mesh 6 is increased, and the second layer of stone pieces 8 is backfilled before the impact drilling is performed again.

[0074] Specifically, the slag sample is analyzed during the drilling process, and it is judged whether the slag soil contains the slag sample of the steel bar mesh 6. If yes, it is indicated that the steel bar 6 is crushed by the impact hammer of the impact drill during the impact process, and the subsequent drilling is easy to be deviated. Therefore, when the slag sample of the steel bar 6 appears, the impact drilling is stopped, the number of layers of the steel bar mesh 6 is increased, and the second layer of stone pieces 8 is backfilled before the impact drilling is performed again, so as to ensure the quality of the subsequent drilling.

[0075] Therefore, if the slag sample of the hole contains the slag sample of the steel bar 6, the impact is stopped. The number of layers of the steel bar mesh 6 is increased, and the second layer of stone pieces 8 is backfilled before the impact drilling is performed again, so as to ensure the quality of the drilling and improve the drilling efficiency.

[0076] Optionally, the method further comprises that, when the pile foundation drilling reaches the inclined hard rock surface, and the steel wire rope of the impact drill swings or an abnormal sound occurs during the punching process, the drilling is stopped.

[0077] Specifically, when the impact hammer of the impact drill approaches the inclined hard rock layer 2, due to the different strengths of the soft rock layer 3 and the hard rock layer 2, the steel wire rope swings due to the slight downward sliding of the impact hammer along the rock boundary line 4, or the impact hammer collides and makes an abnormal sound due to the obstruction of the hard rock layer 2, in either case, the drilling needs to be stopped to avoid subsequent continuous drilling to cause the inclined hole, and at the same time, the protection of the impact hammer can be achieved by avoiding the eccentric loading of the impact hammer.

[0078] Thus, by stopping the drilling when the pile foundation drilling reaches the inclined hard rock surface and the steel wire rope of the impact drill swings or an abnormal sound occurs during the punching process, the working condition of the impact hammer drilling can be effectively determined in time, the impact hammer damage is avoided to prolong the drilling construction time, and the drilling efficiency is improved.

[0079] Although the present application has been disclosed as above, the protection scope of the present application is not limited to this. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present application, and these changes and modifications shall fall within the protection scope of the present application.

Claims

1. A method of drilling a hard batter rock face cast-in-place pile, characterised by , comprising: determining the position of the weak rock layer of the pile hole; inserting the first excess reinforcement of the pile foundation reinforcement cage main reinforcement along the axial direction of the pile hole into the weak rock layer, and backfilling the first layer of stone; pressing the first excess reinforcement and the first layer of stone into the weak rock layer by using the percussion drill; making the second excess reinforcement of the pile foundation reinforcement cage main reinforcement into a reinforcement mesh, and filling the reinforcement mesh horizontally into the pile hole; the number of layers of the reinforcement mesh arranged near the side of the hard rock layer is one layer, and the number of layers of the reinforcement mesh arranged near the side of the weak rock layer is multiple layers; backfilling the second layer of stone on the reinforcement mesh; impacting the second layer of stone by using the percussion drill; drilling a hole.

2. The method according to claim 1, wherein, The thickness of the first layer of stone is KDtanθ / 2, where D is the diameter of the pile hole, θ is the angle of the inclined rock surface, and K is the compaction degree of the weak rock layer.

3. The method of drilling a cast-in-place pile according to claim 1, wherein Further comprising periodically detecting the hole depth during the impacting process of the percussion drill, and stopping the impacting when the difference between the elevation of the hole bottom and the elevation of the highest point of the inclined rock surface is in the range of 0.3-0.5 m.

4. The method of drilling a cast-in-place pile according to claim 1, wherein Further comprising: During the drilling and impacting process of the percussion drill, the value range of the specific gravity of the mud is 1.2-1.

4.

5. The method of drilling a cast-in-place pile according to claim 1, wherein The value range of the spacing d between two adjacent reinforcements of the reinforcement mesh is 0.15-0.3 m, and the diameter of the reinforcement mesh is 10 cm smaller than the diameter of the pile hole.

6. The method of drilling a cast-in-place pile according to claim 1, wherein The value range of the thickness of the second layer of stone is 0.3-0.5 m, and the value range of the block diameter of the second layer of stone is 0.5-0.8 m.

7. The method of drilling a cast-in-place pile according to claim 1, wherein Further comprising: in step three, when the percussion drill impacts the second layer of stone, the value range of the stroke of the percussion drill is 0.5-1 m.

8. The method of drilling a cast-in-place pile according to claim 1, wherein Further comprising: If the slag sample of the drilled hole contains steel slag, stop impacting; Increase the number of layers of the reinforcement mesh, and backfill the second layer of stone before performing the percussion drilling.

9. The method of drilling a cast-in-place pile according to claim 1, wherein Further comprising: when the pile foundation drilling reaches the inclined hard rock surface, and the steel wire rope of the percussion drill swings or an abnormal sound occurs during the punching process, stop drilling.

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