CN114808938A - Construction method for rotary digging pile in boulder final hole - Google Patents

Abstract

The invention discloses a construction method of a rotary excavating pile in a final hole in an boulder, which comprises the following steps: obtaining the horizontal projection area of the boulder according to the characteristic value of the bearing capacity of the single pile of the rotary excavating pile and the characteristic value of the bearing capacity of the pile end of the rotary excavating pile; obtaining the depth of the rotary excavating pile entering the boulder according to the horizontal projection area of the boulder; and placing the rotary excavating pile in a final hole in the boulder. According to the technical scheme, the final hole is formed in the boulder under the condition that the rotary excavating pile meets the requirement of bearing capacity, a large amount of boulder drilling amount does not need to be drilled, the investment of manpower and material resources is saved, and the project construction cost is reduced.

Description

Construction method of final hole of rotary excavation pile in boulder

technical field

The invention relates to the technical field of construction, in particular to a construction method for a final hole of a rotary excavation pile in a boulder.

Background technique

The application of rotary excavation piles is very common in engineering. Generally, the bearing layer of the pile end of rotary excavation piles is in stable moderately weathered and slightly weathered rock layers. However, when there are a large number of large-sized boulders in the construction site, the rotary excavation piles are difficult to reach. Stabilize the rock formation for the final hole. In order to stabilize the final hole of the rock formation, the rotary excavation pile needs to drill through a large amount of boulders, which greatly increases the amount of diamond engineering. Due to the low efficiency and difficulty of diamonds, a large amount of engineering cost increases and construction period is prolonged.

SUMMARY OF THE INVENTION

The main purpose of the present invention is to provide a construction method for the final hole of the rotary excavation pile in the boulder, aiming to solve the problem that the rotary excavation pile is difficult to reach the stable rock formation for the final hole when there are a large number of large-sized boulders in the construction site.

In order to achieve the above object, the construction method of the final hole of the rotary excavation pile in the boulder proposed by the present invention comprises the following steps:

Step 1: Obtain the horizontal projected area of the boulder according to the characteristic value of the single pile bearing capacity of the rotary excavation pile and the characteristic value of the pile end bearing capacity of the rotary excavation pile;

Step 2: obtaining the depth of the rotary excavation pile into the boulder according to the horizontal projected area of the boulder;

Step 3: Make the end hole of the rotary excavation pile in the boulder.

In one embodiment, the step 1 includes:

The characteristic value of the single pile bearing capacity of the rotary excavation pile is set to Ra, the characteristic value of the pile end bearing capacity of the rotary excavation pile is qpa, and the horizontal projected area of the boulder is A _P , A _P ≥ 2.0Ra/ qpa.

In one embodiment, the step 2 includes:

The boulder is set to be an ellipsoid, the horizontal projection length of the boulder is L, the depth of the rotary excavation pile entering the boulder is H, A _P =π*(L/2) ² ;

Taking L=H, the value range of calculating the depth H of the rotary excavation pile into the boulder is:

In one embodiment, the construction method further comprises the steps of:

Step 4: After the construction of the rotary excavation pile is completed, a compression static load test and an uplift static load test are performed on the rotary excavation pile.

In one embodiment, the boulder is in a fully weathered granite soil layer.

In one embodiment, the boulder is in a heavily weathered granite soil layer.

In one embodiment, the step 3 includes the following steps:

Stakeout positioning: Before the project starts, according to the pile position layout of the rotary excavation piles, a measurement control network is established in the site, and then the center points of the pile positions of each of the rotary excavation piles are measured and placed according to the measurement control network;

The rotary excavator is in place: the rotary excavator is in place according to the pile position of the rotary excavation pile;

Embedding the casing: burying and positioning the casing according to the pile position of the rotary excavation pile;

Drilling by rotary excavator: After the casing is buried and positioned, the rotary excavator is used to drill according to the calculated H;

Hole cleaning: after the drilling of the rotary excavator is completed, the drill bit of the rotary excavator is lowered to the bottom of the pile hole of the rotary excavation pile and then slowly rotated to remove the residual mud;

Reinforcement cage fabrication and placement: The rebar cages are produced in sections on site, and are inspected section by section. After passing the inspection, they are listed for storage. After the rebar cages are welded, they are slowly lowered into the pile holes of the rotary excavation piles;

Down pipe: before the pipe is used, the appearance inspection and docking inspection are carried out on the pipe, and the length of the pipe is equipped according to the rotary excavation pile;

Concrete pouring: carry out concrete pouring according to the pile hole of the rotary excavation pile;

Pulling the protective tube: after the concrete pouring is completed, the protective tube is pulled up;

Backfilling of the pile hole: After the concrete is poured, the unconcreted part of the upper part is backfilled with the soil and slag in the site. After the backfill is full, the hole of the rotary excavation pile is re-sealed with concrete.

The technical scheme of the present invention includes the following steps: obtaining the horizontal projected area of the boulder according to the characteristic value of the single pile bearing capacity of the rotary excavation pile and the characteristic value of the pile end bearing capacity of the rotary excavation pile; The depth of the rotary excavation pile into the boulder is obtained from the horizontal projected area; the rotary excavation pile is finished in the boulder. By carrying out the final hole in the boulder under the condition that the rotary excavation pile meets the bearing capacity requirements, there is no need to drill through the boulder in a large amount, which is beneficial to save the investment of manpower and material resources and reduce the construction cost of the project.

Description of drawings

In order to explain the embodiments of the present invention or the technical solutions in the prior art more clearly, the following briefly introduces the accompanying drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only These are some embodiments of the present invention, and for those of ordinary skill in the art, other drawings can also be obtained according to the structures shown in these drawings without creative efforts.

FIG. 1 is a schematic structural diagram of an embodiment of a construction method for a final hole in a boulder of a rotary excavated pile of the present invention.

Description of reference numbers:

label name label name 100 Rotary pile 300 residual soil layer 200 boulder 400 Fully weathered granite soil/strongly weathered granite soil

The realization, functional characteristics and advantages of the present invention will be further described with reference to the accompanying drawings in conjunction with the embodiments.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

It should be noted that if there are directional indications (such as up, down, left, right, front, back, etc.) involved in the embodiments of the present invention, the directional indications are only used to explain a certain posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication also changes accordingly.

In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only used for the purpose of description, and should not be construed as indicating or implying Its relative importance or implicitly indicates the number of technical features indicated. Thus, a feature delimited with "first", "second" may expressly or implicitly include at least one of that feature. In addition, if the meaning of "and/or" appears in the whole text, it includes three parallel schemes, taking "A and/or B" as an example, including scheme A, or scheme B, or the scheme that A and B satisfy at the same time . In addition, the technical solutions between the various embodiments can be combined with each other, but must be based on the realization by those of ordinary skill in the art. When the combination of technical solutions is contradictory or cannot be realized, it should be considered that the combination of such technical solutions does not exist. , is not within the scope of protection required by the present invention.

The rotary excavation pile 100 is widely used in engineering. Generally, the pile end bearing layer of the rotary excavation pile 100 is in stable moderately weathered and slightly weathered rock layers. However, when there are a large number of large-sized boulders 200 in the construction site, the rotary excavation It is difficult for the pile 100 to reach the stable rock formation for final hole. If the rotary excavation pile 100 needs to drill through the boulder 200 in order to stabilize the final hole in the rock formation, it will greatly increase the amount of diamond engineering. Due to the low efficiency and difficulty of diamond, a large amount of engineering cost increase and construction period are prolonged.

Referring to FIG. 1, the present invention proposes a construction method for the final hole of the rotary excavation pile 100 in the boulder 200, and the construction method includes the following steps:

Step 1: Obtain the horizontal projected area of the boulder 200 according to the characteristic value of the single pile bearing capacity of the rotary excavation pile 100 and the characteristic value of the pile end bearing capacity of the rotary excavation pile 100;

Step 2: obtaining the depth of the rotary excavation pile 100 entering the boulder 200 according to the horizontal projected area of the boulder 200;

Step 3: Finish the hole in the boulder 200 with the rotary excavation pile 100 .

Specifically, the bearing capacity of a single pile means that under the load of the single pile of the rotary excavation pile 100, the strength and stability of the foundation soil and the rotary excavation pile 100 itself can be guaranteed, and the deformation is also within the allowable range to ensure that the structure The maximum load that can be endured in normal use. The bearing capacity of the pile end is shown in Figure 1. The depth of the rotary excavation pile 100 entering the boulder 200 is obtained by calculation, so that the rotary excavation pile 100 is subjected to a final hole in the boulder 200 under the condition that the bearing capacity requirements are met, so that there are a large number of large-sized boulders 200 in the construction site. If the rotary excavation pile 100 is to be kept stable, there is no need to drill through the boulder 200 in large quantities, which greatly reduces the drilling volume of the boulder 200 of the engineering pile and the engineering volume of the engineering pile, which is beneficial to save the investment of manpower and material resources and reduce the construction of the project. cost, save the construction period of the project, and achieve the purpose of reducing cost and increasing efficiency.

In one embodiment, the step 1 includes: setting the characteristic value of the single pile bearing capacity of the rotary excavation pile 100 to Ra, the characteristic value of the pile end bearing capacity of the rotary excavation pile 100 to qpa, and the characteristic value of the boulder The horizontal projected area of 200 is _AP , _AP ≥2.0Ra/qpa. It can be understood that the horizontal projected area _AP of the boulder 200 multiplied by the characteristic value qpa of the pile end bearing capacity of the rotary excavation pile 100 should not be less than the designed characteristic value Ra of the single pile bearing capacity of the rotary excavation pile 100, which can be calculated by calculation. Reversely find the horizontal projected area of the boulder 200 .

可以理解的是，设计假定孤石200为椭圆体，近似取孤石200水平投影长度L等于旋挖桩100进入孤石200内的深度H，将孤石200视做旋挖桩100桩端扩大头。通过孤石200的水平投影面积A_P乘以旋挖桩100的桩端承载力特征值qpa不应小于设计的旋挖桩100的单桩承载力特征值Ra，可以通过运算来反求出旋挖桩100进入孤石200内的深度

按上述要求经计算可得在不同土层时，旋挖桩100进入孤石200内的深度H可以终孔。如此将旋挖桩100在满足承载力要求的情况下在孤石200内进行终孔，使得对施工场地内存在大量大尺寸孤石200时，旋挖桩100要保持稳定的话，无需大量钻穿孤石200，大大减少了工程桩的孤石200钻进量和工程桩的工程量。In one embodiment, the step 2 includes: setting the boulder 200 to be an ellipsoid, the horizontal projection length of the boulder 200 is L, and the depth of the rotary excavation pile 100 entering the boulder 200 is H, A _P =π*(L/2) ² ; taking L=H, the value range for calculating the depth H of the rotary excavation pile 100 entering the boulder 200 is:

It can be understood that the design assumes that the boulder 200 is an ellipsoid, and the horizontal projection length L of the boulder 200 is approximately equal to the depth H of the rotary excavation pile 100 into the boulder 200, and the boulder 200 is regarded as the expansion of the end of the rotary excavation pile 100. head. By multiplying the horizontal projected area _AP of the boulder 200 by the characteristic value qpa of the pile end bearing capacity of the rotary excavation pile 100, it should not be less than the designed characteristic value Ra of the single pile bearing capacity of the rotary excavation pile 100. Depth of digging pile 100 into boulder 200

According to the above requirements, it can be calculated that the depth H of the rotary excavation pile 100 entering the boulder 200 can be the final hole in different soil layers. In this way, the rotary excavation pile 100 is finished in the boulder 200 under the condition that the bearing capacity requirements are met, so that when there are a large number of large-sized boulders 200 in the construction site, if the rotary excavation pile 100 is to remain stable, it is not necessary to drill through a large number of holes. The boulder 200 greatly reduces the drilling volume of the boulder 200 of the engineering pile and the engineering volume of the engineering pile.

In order to ensure the construction quality, the quality of the rotary excavation pile 100 also needs to be tested. In one embodiment, the construction method further includes step 4: after the construction of the rotary excavation pile 100 is completed, the anti-corrosion process of the rotary excavation pile 100 is carried out. Compression static load test and pullout static load test. During the compressive testing of the rotary excavated piles 100, some rotary excavated piles 100 with final holes in the boulders 200 are selected to carry out the compressive static load test and the anti-uplift static load test. After third-party testing, it is judged whether the vertical compressive bearing capacity and vertical uplift bearing capacity of the single pile meet the design requirements.

When the boulder 200 is in the soil layer above the fully weathered granite, the rotary excavation pile 100 can selectively penetrate. In one embodiment, the boulder 200 is within a fully weathered granite soil layer 400 . Optionally, the rotary excavation pile 100 enters a 4.5-meter end hole in the boulder 200 . In yet another embodiment, the boulder 200 is in a strongly weathered granite soil layer 400 . Optionally, the rotary excavation pile 100 enters the 3.7-meter end hole in the boulder 200 .

The construction is carried out according to the depth H at which the rotary excavation pile 100 enters the boulder 200 obtained by the assumed design and calculation. Step 3 includes the following steps:

(1) Stakeout positioning: Before the project starts, according to the pile position layout of the rotary excavation piles 100, a measurement control network is established in the site, and then the pile position of each of the rotary excavation piles 100 is measured and placed according to the measurement control network. the center point.

(2) Rotary excavator in place: The rotary excavator is in place according to the pile position of the rotary excavation pile 100. The rotary excavator must be stable, square, level, positioned, and the error between the center of the drill bit and the center of the pile position is not more than 10mm .

(3) Embedding the casing: The casing is buried and positioned according to the pile position of the rotary excavation pile 100. The diameter of the casing should be 200mm larger than the diameter of the pile hole, and the circumference of the casing should be backfilled with clay and compacted in layers.

(4) Drilling by rotary excavator: After the casing is buried and positioned, the rotary excavator is used to drill according to the calculated H.

In the process of hole forming by the rotary excavator, mud wall protection can be used. The mud is naturally made by the stirring effect of the drill bit on the soil during the drilling process, and the specific gravity of the mud is adjusted according to the actual needs. The mud forms a mud skin on the surface of the hole wall during the circulation process, and the self-weight of the mud and the mud protect the hole wall , to prevent the hole wall from collapsing.

(5) Hole cleaning: after the drilling of the rotary excavator is completed, the drill bit of the rotary excavator is lowered to the bottom of the pile hole of the rotary excavation pile 100 and then slowly rotated to remove the residual mud.

(6) Fabrication and placement of steel cages:

1. Reinforcement cage production: Reinforcement cages are produced in sections on site, the main reinforcement and reinforcement are all welded, and the spiral reinforcement and the main reinforcement are reinforced by spot welding. The reinforcement cage production needs to meet the design requirements. The finished steel cages are checked and accepted section by section, and they are listed for storage after passing the inspection.

2. Placement in the hole of the rebar cage: After the rebar is well welded, it should be slowly lowered into the hole, and it is strictly forbidden to smash the cage.

(7) Downpipe:

Before the conduit is used, perform visual inspection and docking inspection on the conduit, and the conduit length is equipped according to the rotary excavation pile 100;

1. Selection of catheter: Before the catheter is used, visual inspection and docking inspection of the catheter must be carried out.

(1) Visual inspection: check whether the conduit is deformed, pitted, bent, and whether there is damage or cracks, etc., and check whether the inner wall is smooth. For new conduits, check whether the inner wall is smooth and whether there is welding slag. Ducts should be inspected for concrete adhesion and consolidation on their inner walls.

(2) Docking inspection: The conduit joint thread should be kept in good condition. After connecting, it should be straight and concentric.

After passing the above inspection, it can be put into use, and the use of unqualified catheters is strictly prohibited. The length of the conduit should be equipped according to the depth of the hole to meet the needs of hole cleaning and concrete pouring.

2. Catheter lowering

The conduit should be firm at the connection of the orifice, and a sealing ring should be provided. When hoisting, the position should be centered, the axis should be straight, and the duct should be placed stably to avoid hanging on the steel cage and scratching the wall of the hole.

(8) Concrete pouring: Concrete pouring is carried out according to the pile hole of the rotary excavation pile 100 .

(9) Pulling out the protective tube: after the concrete pouring is completed, the protective tube is pulled up.

(10) Backfilling of the pile hole: After the concrete is poured, the unconcreted part of the upper part is backfilled with the soil and slag in the site. After the backfill is full, the hole of the rotary excavation pile 100 is re-sealed with concrete.

The above descriptions are only optional embodiments of the present invention, and are not intended to limit the scope of the present invention. Under the inventive concept of the present invention, any equivalent structural transformations made by using the contents of the description and drawings of the present invention, or direct/indirect Applications in other related technical fields are included in the scope of patent protection of the present invention.

Claims (7)

1. a construction method of rotary excavation pile in boulder end hole, is characterized in that, described construction method comprises the following steps: Step 1: Obtain the horizontal projected area of the boulder according to the characteristic value of the single pile bearing capacity of the rotary excavation pile and the characteristic value of the pile end bearing capacity of the rotary excavation pile; Step 2: obtaining the depth of the rotary excavation pile into the boulder according to the horizontal projected area of the boulder; Step 3: Make the end hole of the rotary excavation pile in the boulder. 2. the construction method of rotary excavation pile in boulder end hole as claimed in claim 1, is characterized in that, described step 1 comprises: The characteristic value of the single pile bearing capacity of the rotary excavation pile is set to Ra, the characteristic value of the pile end bearing capacity of the rotary excavation pile is qpa, and the horizontal projected area of the boulder is A _P , A _P ≥ 2.0Ra/ qpa. 3. the construction method of the final hole of the rotary excavation pile in the boulder as claimed in claim 2, is characterized in that, described step 2 comprises: The boulder is set to be an ellipsoid, the horizontal projection length of the boulder is L, the depth of the rotary excavation pile entering the boulder is H, A _P =π*(L/2) ² ; Taking L=H, the value range of calculating the depth H of the rotary excavation pile into the boulder is:

4. the construction method of rotary excavation pile in boulder end hole as claimed in claim 1, is characterized in that, described construction method also comprises the steps: Step 4: After the construction of the rotary excavation pile is completed, a compression static load test and an uplift static load test are performed on the rotary excavation pile. 5 . The construction method of the final hole of the rotary excavation pile in the boulder according to claim 1 , wherein the boulder is in a fully weathered granite soil layer. 6 . 6 . The construction method for the final hole of the rotary excavation pile in the boulder according to claim 1 , wherein the boulder is in a strongly weathered granite soil layer. 7 . 7. the construction method of rotary excavation pile in boulder end hole as claimed in claim 1, is characterized in that, described step 3 comprises the following steps: Stakeout positioning: Before the construction of the project, according to the pile position layout of the rotary excavation piles, a measurement control network is established in the site, and then the center points of the pile positions of each of the rotary excavation piles are measured and placed according to the measurement control network; The rotary excavator is in place: the rotary excavator is in place according to the pile position of the rotary excavation pile; Embedding the casing: burying and positioning the casing according to the pile position of the rotary excavation pile; Rotary excavator forming a hole: after the casing is buried and positioned, the rotary excavator is used to drill according to the calculated H; Hole cleaning: after the drilling of the rotary excavator is completed, the drill bit of the rotary excavator is lowered to the bottom of the pile hole of the rotary excavation pile and then slowly rotated to remove the residual mud; Reinforcement cage fabrication and placement: The rebar cages are produced in sections on site, and are checked and accepted section by section. After passing the qualification, they are listed for storage. After the rebar cages are welded, they are slowly put into the pile holes of the rotary excavation piles; Down pipe: before the pipe is used, the appearance inspection and docking inspection are carried out on the pipe, and the length of the pipe is equipped according to the rotary excavation pile; Concrete pouring: carry out concrete pouring according to the pile hole of the rotary excavation pile; Pulling the protective tube: after the concrete pouring is completed, the protective tube is pulled up; Backfilling of the pile hole: After the concrete is poured, the unconcreted part of the upper part is backfilled with the soil and slag in the site. After the backfill is full, the hole of the rotary excavation pile is re-sealed with concrete.

Images