Construction technology of slurry-supported cast-in-place pile by rotary drilling rig

Abstract

The present invention belongs to the technical field of the construction technology of rotary drilling rigs, and provides a construction process for slurry-supported cast-in-place piles of rotary drilling rigs, including: site leveling; sequentially arranging a first pile, an orifice slurry pit, a second pile and a slurry pit on one side of the rotary drilling rig; the rotary drilling rig excavates the first pile hole, the slurry pit, the orifice slurry pit and the second pile hole; installs steel casing into the first pile hole and the second pile hole; digs drainage grooves on the retaining walls of the first pile hole and the second pile hole, and the drainage grooves communicate with the orifice slurry pit; the rotary drilling rig drills and clears the holes; lowers steel reinforcement cages and conduits into the first pile hole and the second pile hole; pours concrete, and after the concrete pouring is completed, pulls out the steel casing from the pile hole to form a pile foundation. The present invention changes the traditional slurry-supported process from a process flow of single pile with three slurry pits to a process flow of double piles with two slurry pits or four piles with three slurry pits, greatly saving labor and mechanical costs, improving efficiency and reducing project costs.

Description

Technical Field

[0001] The invention belongs to the technical field of rotary drilling rig construction, and in particular relates to a rotary drilling rig mud wall protection cast-in-place pile construction process. Background Art

[0002] The statements in this section merely provide background information related to the present invention and do not necessarily constitute prior art.

[0003] The rotary drilling rig is a comprehensive drilling rig that can be used in a variety of strata. It has the characteristics of fast hole-making speed, less pollution, and strong mobility. It can use a short spiral drill bit for dry digging, a rotary drill bit for wet digging with mud wall protection, or a hammer to break the hard stratum for digging. If used with an enlarged head drill, the hole can be enlarged at the bottom of the hole. The rotary drilling rig uses a multi-layer telescopic drill rod, which has less drilling auxiliary time, low labor intensity, no need for mud circulation and slag removal, and saves costs. It is particularly suitable for the foundation construction of urban construction.

[0004] The rated power of rotary drilling rigs is generally 125-450kW, the power output torque is 120-400kN·m, the maximum hole diameter can reach 1.5-4m, and the maximum hole depth is 60-90m, which can meet the requirements of various large-scale foundation construction. This type of drilling rig generally adopts hydraulic crawler telescopic chassis, self-lifting and foldable drilling mast, telescopic drill rod, automatic vertical detection and adjustment, digital display of hole depth, etc. The whole machine operation generally adopts hydraulic pilot control and load sensing, which is easy and comfortable to operate.

[0005] With the increase of engineering projects in recent years, more and more construction methods using rotary drilling rig mud wall cast-in-place piles are being used. Therefore, it is very necessary to conduct necessary research on construction technology.

[0006] At present, the construction technology of rotary bored piles mostly refers to the relevant provisions of the Technical Specifications for Building Pile Foundations (JGJ 94-2008). The construction process of each pile is roughly as follows: ① site leveling - ② mud preparation - ③ measuring and placing pile positions - ④ drilling holes and burying casings - ⑤ drilling to the designed hole depth - ⑥ setting up a steel cage - ⑦ installing guide tubes and hoppers - ⑧ pouring concrete - ⑨ moving the drill to the next pile.

[0007] The traditional rotary drilling rig construction constructs one pile each time, and the mud wall construction process (corresponding to the ② mud preparation in the previous section) usually sets up three mud pools, the first is the hole mud pool, the second is the sedimentation pool, and the third is the mud preparation pool. This traditional construction process has the following disadvantages: 1) Low efficiency: slow hole formation, only one pile can be constructed each time; 2) Large area: setting up three mud pools occupies a lot of space, which is not conducive to pile foundation construction in a small site; 3) High cost: large amount of mud is used, and the mud infiltration in the three mud pools and the loss during pipeline transportation are relatively large. Summary of the invention

[0008] In order to solve the above problems, the present invention proposes a rotary drilling rig mud wall cast-in-place pile construction process, which transforms the traditional mud wall protection process from a single-pile three-mud pool process flow to a double-pile double-mud pool or a four-pile three-mud pool process flow, greatly saving labor and machinery costs, improving efficiency, reducing engineering costs, and being more suitable for narrow sites.

[0009] According to some embodiments, the present invention adopts the following technical solutions:

[0010] In a first aspect, the present invention provides a rotary drilling rig mud wall cast-in-place pile construction process.

[0011] This is a double pile and double mud pool process, a rotary drilling rig mud wall cast-in-place pile construction process, including:

[0012] The site is level;

[0013] A first pile, a hole mud pool, a second pile and a mud pool are sequentially arranged on one side of the rotary drilling rig;

[0014] The rotary drilling rig excavates the first pile hole, the mud pool, the hole mouth mud pool and the second pile hole;

[0015] Installing steel casings into the first pile hole and the second pile hole;

[0016] Digging drainage grooves on the retaining wall of the first pile hole and the retaining wall of the second pile hole, wherein the drainage grooves are connected to the mud pool at the hole mouth;

[0017] Drilling and hole cleaning with rotary drilling rig;

[0018] Lower the steel cage and the guide tube into the first pile hole and the second pile hole;

[0019] Pour concrete. After the concrete pouring is completed, pull the steel casing out of the pile hole to form a pile foundation.

[0020] In a second aspect, the present invention provides a rotary drilling rig mud wall cast-in-place pile construction process.

[0021] This process belongs to the process flow of four piles and three slurry pits, a construction process for bored piles with slurry support by a rotary drilling rig, including:

[0022] Site leveling;

[0023] Set the first pile, the first orifice slurry pit, the second pile, the slurry pit, the third pile, the second orifice slurry pit, and the fourth pile in sequence on one side of the rotary drilling rig;

[0024] The rotary drilling rig excavates the first pile hole, the slurry pit, the orifice slurry pit, and the second pile hole;

[0025] Install steel casing into the first pile hole and the second pile hole;

[0026] Dig drainage grooves on the retaining walls of the first pile hole and the second pile hole, and the drainage grooves are interconnected with the orifice slurry pit;

[0027] The rotary drilling rig drills and clears the hole;

[0028] Lower the steel reinforcement cage and the conduit into the first pile hole and the second pile hole;

[0029] Pour concrete. After the concrete pouring is completed, pull out the steel casing from the pile hole to form a pile foundation.

[0030] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0031] 1. By excavating the soil between two casings, the present invention forms a large-sized orifice slurry pit, which can simultaneously function as a sedimentation tank, eliminating the traditional sedimentation tank and reducing the excavation workload. When constructing the first pile, the excess slurry can flow into the casing of the second pile, reducing the slurry loss and infiltration. Since the two piles are relatively close, this construction method also reduces the cost of transporting muck out of the site; field practice has proved that this process reduces the cost by about 20% compared with the traditional construction process.

[0032] 2. The present invention improves the efficiency. Taking two piles as a group, compared with the traditional process of constructing single piles one by one, the construction is faster, the efficiency is higher, and the in-site transfer times of machinery such as excavators, rotary drilling rigs, and loaders are fewer.

[0033] 3. The present invention saves the site. By adjusting from three slurry pits to two slurry pits, the number of slurry pits is reduced, saving the site and being more suitable for narrow sites.

[0034] 4. The present invention saves the slurry consumption. The reduction in the number of slurry pits will correspondingly reduce the slurry infiltration and the loss during pipeline transportation, thus achieving the effect of saving the slurry consumption.

[0035] 5. The present invention reduces the transportation cost of the slag. Since the two piles are close to each other, the slag at the excavation sites of the two piles can be piled nearby and transported in batches, thus reducing the transportation cost of the slag. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The accompanying drawings in the specification, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0037] Figure 1 It is a construction process flow chart of a double-pile double-tank method for rotary drilling rig mud wall concrete cast-in-place piles shown in the first embodiment of the present invention;

[0038] Figure 2 It is a traditional construction process diagram introduced in the embodiment of the present invention;

[0039] Figure 3 This is a construction process diagram of a double-pile double-tank method for rotary drilling rig mud wall concrete cast-in-place piles shown in the first embodiment of the present invention;

[0040] Among them, 1. steel casing, 2. hole mouth mud pool, 3. first mud pump, 4. second mud pump, 5. mud pool, 6. first pile hole, 7. second pile hole, 8. sediment in mud, 9. sedimentation tank. DETAILED DESCRIPTION

[0041] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0042] It should be noted that the following detailed descriptions are exemplary and are intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.

[0043] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0044] In the description of this specification, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0045] As introduced in the background art, for the traditional construction process of slurry-supported bored piles of rotary drilling rigs, see Figure 2 , and the specific method is as follows: During drilling, first prepare slurry in the slurry pit 5, and then use the first slurry pump 3 to transport the slurry to the orifice slurry pit 2 through the slurry supply pipeline; during hole cleaning, use the second slurry pump 4 to transport the slurry to the sedimentation tank 9 through the return slurry pipeline. At this time, the sediment 8 (impurities) in the slurry will settle to the bottom of the sedimentation tank 9, and the clean slurry will continue to flow back to the slurry pit 5, thus completing the process of slurry circulation. It can be seen that there is a first pile hole 6 and a steel casing 1 in the traditional construction process of slurry-supported bored piles of rotary drilling rigs. Usually, three slurry pits are set up. The first one is the orifice slurry pit, the second two are sedimentation tanks, and the third one is the slurry preparation pit. This construction process not only has low efficiency, occupies a large area but also has high costs. To solve the above problems, the present invention provides a construction process for slurry-supported bored piles of rotary drilling rigs, which will be introduced through various embodiments as follows:

[0046] Embodiment 1

[0047] This embodiment provides a construction process for slurry-supported bored piles of rotary drilling rigs.

[0048] As Figure 1 , Figure 3 shown, a construction process for slurry-supported bored piles of rotary drilling rigs includes:

[0049] Taking the pile cap as a unit, taking two piles as a group, and doing construction preparation work;

[0050] Among them, the construction preparation work includes: measuring and setting out, leveling the foundation, detecting the levelness of the construction site, calculating the pile position according to the construction design drawings and making marks;

[0051] According to the marked pile positions, sequentially set the first pile, the orifice slurry pit 2, the second pile and the slurry pit 5 on one side of the rotary drilling rig;

[0052] Using a pile driver or a rotary drilling rig, bury the steel casings 1 of the two piles into the soil. Excavate the soil between the two steel casings 1 to form a large-sized orifice slurry pit 2, and deepen the middle part of the orifice slurry pit 2 to serve as a sedimentation tank; use this orifice slurry pit 2 to replace the traditional sedimentation tank; among them, the process of burying the steel casings 2 of the two piles into the soil includes: using the rotary drilling rig to drill to the embedding depth, installing a casing driver on the rotary drilling rig, lifting the steel casing 2, aligning it with the hole position, and lowering the rotating arm to install the steel casings 2 of the two piles.

[0053] As one or more embodiments, after excavating the slurry pit 5, it includes: preparing slurry, injecting clean water into the slurry pit 5, adding slurry powder into the slurry pit 5 along with the clean water, and stirring evenly to obtain slurry.

[0054] Dig drainage grooves on the retaining walls of the first pile hole 6 and the second pile hole 7, and the drainage grooves communicate with the orifice mud pit 2;

[0055] Construct the first pile, and the rotary drilling rig drills and conducts the first hole cleaning;

[0056] Lower the steel reinforcement cage and the conduit into the first pile hole and the second pile hole;

[0057] Conduct the second hole cleaning;

[0058] Pour concrete. After the concrete pouring is completed, pull out the steel casing from the pile hole to form a pile foundation;

[0059] After the pouring is completed and waiting for at least half a day, then construct the second pile.

[0060] As one or more embodiments, the rotary drilling rig drilling and hole cleaning specifically includes: pouring mud into the orifice mud pit 2, and the mud enters the first pile hole 6 through the drainage groove; the first hole cleaning, pumping out the cement slurry and muck in the first pile hole 6.

[0061] As one or more embodiments, the process of pouring mud into the orifice mud pit 2 and the mud entering the first pile hole 6 through the drainage groove includes: a first mud pump 3 and a first return slurry pipeline are provided between the mud pit 5 and the orifice mud pit 2, and the first mud pump 3 is used to transport the mud to the orifice mud pit through the first return slurry pipeline, and the mud in the orifice mud pit 2 enters the first pile hole 6 through the drainage groove.

[0062] As one or more embodiments, the process of the first hole cleaning includes: a second mud pump 4 and a second return slurry pipeline are provided between the mud pit and the orifice mud pit. During hole cleaning, the second mud pump 4 is used to transport the mud to the mud pit through the second return slurry pipeline.

[0063] As one or more embodiments, the second hole cleaning includes: if the bottom sediment in the hole is greater than the set value, conduct the second hole cleaning and pump out the cement slurry and muck in the first pile hole.

[0064] The following is a specific introduction to the hole cleaning process. In order to clean the sediment at the bottom of the hole as thoroughly as possible, the replacement slurry method is adopted for secondary hole cleaning in this embodiment. That is, after drilling is completed, the drill bit is raised about 20 cm above the bottom of the hole. Relatively pure slurry with a specific gravity of 1.02 - 1.2 is pressed in at a medium speed to replace the slurry with more suspended drill cuttings in the borehole. After measurement, the sediment at the bottom of the hole is no more than 30 cm, and the first hole cleaning is completed. The drill is lifted to install the steel reinforcement cage and the conduit. After the conduit is installed, the thickness of the sediment layer is re-measured for the second hole cleaning. When the relative density of the slurry within 500 mm from the bottom of the hole is less than 1.25; the sand content is no more than 8%; the viscosity is no more than 28 s; the thickness of the sediment at the bottom of the hole is no more than 50 mm for end-bearing piles, no more than 100 mm for friction piles, and no more than 200 mm for uplift and horizontal force resistance piles, it meets the requirements. After hole cleaning, the first batch of concrete should be poured within 30 minutes to prevent the suspension from settling again and ensure that the thickness of the sediment at the bottom of the hole meets the design requirements.

[0065] In this embodiment, the traditional technological process of a single pile with three ponds is transformed into a technological process of two piles with two ponds, and the above technical measures are taken. It has been confirmed by actual engineering practice that the comprehensive cost is reduced by about 20% compared with the traditional construction technology.

[0066] As one or more embodiments, if an abnormality occurs when pouring concrete into the first pile hole 6, the second pile hole 7 is backfilled.

[0067] As one or more embodiments, the abnormality includes: cross-hole and / or slurry gushing.

[0068] As one or more embodiments, sediment will gradually form in the middle of the deepened orifice mud pit and slowly fill the deepened position. If the sediment formed in the middle of the deepened orifice mud pit exceeds the set height, an excavator is used to clean the sediment; or an excavator is used for cleaning every once in a while (3 - 5 hours).

[0069] This process is not applicable to the situation where the distance between two piles is too small (clear distance < 3 times the pile diameter) because it will cause hole collapse.

[0070] This embodiment solves the shortcomings of the traditional construction technology and has the following advantages:

[0071] 1) High efficiency: Fast hole formation, and 2 piles can be constructed each time;

[0072] 2) Small land occupation: The number of mud pits is reduced to 2, occupying less land, and it is more suitable for pile foundation construction in narrow sites;

[0073] 3) Low cost: The reduction in the number of mud pits will correspondingly reduce the seepage of the slurry and the loss during pipeline transportation, thus achieving the effect of saving slurry consumption.

[0074] Embodiment 2

[0075] This embodiment provides a rotary drilling rig mud wall cast-in-place pile construction process.

[0076] A rotary drilling rig mud wall cast-in-place pile construction process, comprising:

[0077] The site is level;

[0078] A first pile, a first hole mud pool, a second pile, a mud pool, a third pile, a second hole mud pool and a fourth pile are sequentially arranged on one side of the rotary drilling rig;

[0079] The rotary drilling rig excavates the first pile hole, the mud pool, the hole mouth mud pool and the second pile hole;

[0080] Installing steel casings into the first pile hole and the second pile hole;

[0081] Digging drainage grooves on the retaining wall of the first pile hole and the retaining wall of the second pile hole, wherein the drainage grooves are connected to the mud pool at the hole mouth;

[0082] Drilling and hole cleaning with rotary drilling rig;

[0083] Lower the steel cage and the guide tube into the first pile hole and the second pile hole;

[0084] Pour concrete. After the concrete pouring is completed, pull the steel casing out of the pile hole to form a pile foundation.

[0085] As one or more implementation modes, the site leveling includes: measuring and laying out, leveling the foundation, performing a levelness check on the construction site, and calculating and marking the pile positions according to the construction design drawings.

[0086] As one or more implementation modes, after the mud pool is excavated, the process includes: preparing mud, injecting clean water into the mud pool, adding mud powder into the mud pool along with the clean water, and stirring evenly to obtain mud.

[0087] As one or more implementation modes, the specific process of installing steel casings into the first pile hole and the second pile hole includes: after drilling to the burial depth using a rotary drilling rig, the rotary drilling rig installs a casing driver, lifts the steel casing, aligns it with the hole position, and lowers the rotating arm to install the steel casings of the two piles.

[0088] As one or more implementation modes, the rotary drilling rig drilling and hole cleaning specifically includes: pouring mud into the mud pool at the hole mouth, and the mud enters the first pile hole through the drainage trough; cleaning the hole for the first time, extracting the cement slurry and slag in the first pile hole out of the first pile hole.

[0089] As one or more embodiments, the process of pouring mud into the orifice mud pit and the mud entering the first pile hole through the drainage trough includes: a first mud pump and a first return slurry pipeline are provided between the mud pit and the orifice mud pit, and the first mud pump is used to transport the mud to the orifice mud pit through the first return slurry pipeline, and the mud in the orifice mud pit enters the first pile hole through the drainage trough.

[0090] As one or more embodiments, the process of the first hole cleaning includes: a second mud pump and a second return slurry pipeline are provided between the mud pit and the orifice mud pit. During hole cleaning, the second mud pump is used to transport the mud to the mud pit through the second return slurry pipeline.

[0091] As one or more embodiments, before pouring concrete, it includes: if the bottom sediment in the hole is greater than the set value, a second hole cleaning is carried out to pump out the cement slurry and muck in the first pile hole.

[0092] As one or more embodiments, if an abnormality occurs during pouring concrete into the first pile hole, the second pile hole is backfilled.

[0093] As one or more embodiments, the abnormality includes: cross-hole and / or slurry gushing.

[0094] As one or more embodiments, when the rotary drilling rig excavates the orifice mud pit, the depth in the middle of the orifice mud pit is deepened.

[0095] As one or more embodiments, if the sediment generated in the deepened middle part of the orifice mud pit exceeds the set height, an excavator is used to clean the sediment.

[0096] In addition, this process is not applicable to the case where the distance between two piles is too small (the net distance < 3 times the pile diameter) because it will cause hole collapse.

[0097] The difference between this embodiment and Embodiment 1 is that this embodiment adopts the construction process of four piles and three pits, further reducing the number of pits, and having the advantages of higher efficiency, smaller land occupation and lower cost.

[0098] The above are only the preferred embodiments of the present invention and are not used to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A construction technology for slurry-supported cast-in-place piles of rotary drilling rigs, characterized in that, Including: Site leveling; Sequentially arranging a first pile, an orifice mud pit, a second pile and a mud pit on one side of a rotary drilling rig; The rotary drilling rig excavates a first pile hole, a mud pit, an orifice mud pit and a second pile hole; After excavating the mud pit, it includes: preparing mud, injecting clear water into the mud pit, adding mud powder into the mud pit along with the clear water, and stirring evenly to obtain mud; Installing steel casing into the first pile hole and the second pile hole; Digging drainage grooves on the retaining walls of the first pile hole and the second pile hole, and the drainage grooves communicate with the orifice mud pit; The rotary drilling rig drills and cleans the holes; the rotary drilling rig drilling and cleaning the holes specifically includes: pouring mud into the orifice mud pit, and the mud enters the first pile hole through the drainage groove; the first hole cleaning, pumping out the cement slurry and muck in the first pile hole; the process of the first hole cleaning includes: there is a second mud pump and a second return slurry pipeline between the mud pit and the orifice mud pit, during hole cleaning, the second mud pump is used to transport the mud to the mud pit through the second return slurry pipeline; the process of pouring mud into the orifice mud pit and the mud entering the first pile hole through the drainage groove includes: there is a first mud pump and a first return slurry pipeline between the mud pit and the orifice mud pit, the first mud pump is used to transport the mud to the orifice mud pit through the first return slurry pipeline, and the mud in the orifice mud pit enters the first pile hole through the drainage groove; Lowering steel reinforcement cages and conduits into the first pile hole and the second pile hole; Pouring concrete, and after the concrete pouring is completed, pulling out the steel casing from the pile hole to form a pile foundation.

2. The construction process of the slurry-supported cast-in-place pile of the rotary drilling rig according to claim 1, characterized in that, The site leveling includes: measuring and setting out lines, leveling the foundation, detecting the levelness of the construction site, calculating the pile position according to the construction design drawings and making marks.

3. The construction process of the slurry-supported cast-in-place pile of the rotary drilling rig according to claim 1, characterized in that, The specific process of installing steel casing into the first pile hole and the second pile hole includes: after using the rotary drilling rig to drill to the embedding depth, installing a casing driver on the rotary drilling rig, lifting the steel casing, aligning the hole position, and lowering and installing the steel casing for two piles by rotating the arm.

4. The construction process of the slurry-supported cast-in-place pile using a rotary drilling rig according to claim 1, characterized in that, Before pouring concrete, it includes: if the bottom sediment in the hole is greater than the set value, conducting a second hole cleaning, and pumping out the cement slurry and muck in the first pile hole.

5. The construction process of the slurry-supported cast-in-place pile using a rotary drilling rig according to claim 1, characterized in that, If an abnormality occurs during pouring concrete into the first pile hole, where the abnormality includes: cross-hole and / or mud gushing, then backfill the second pile hole; Or, When the rotary drilling rig excavates the orifice mud pit, deepen the depth of the middle part of the orifice mud pit; Or, If the sediment generated in the deepened middle part of the orifice mud pit exceeds the set height, use an excavator to clean the sediment.

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