Construction system and method of hard rock drilling for interlocking piles in foundation pits in height-restricted areas

Abstract

The invention discloses a hard rock drilling construction system and a construction method for interlocking piles in a height-restricted area foundation pit, and belongs to the technical field of cast-in-place pile construction. The construction system comprises a full-casing rotary drilling rig and an improved drilling rig for construction in a height-restricted area and a hard rock layer. The hard rock layer comprises an upper soil layer and a lower rock layer. The full-casing rotary drilling rig drives a casing assembly to form a hole in the upper soil layer, and the improved drilling rig drives a down-the-hole hammer to form a hole in the lower rock layer. The height of the improved drilling rig is lower than that of the height-restricted area, and the down-the-hole hammer is connected through a drill rod assembly. The drill rod assembly consists of a plurality of short drill rods connected end to end. The top end of any short drill rod is disconnected and a new short drill rod is added to lengthen the length of the drill rod assembly. The problem that the rotary drilling machine used in the prior art has low efficiency and the rotary drilling drill bit is extremely easy to be damaged is solved.

Description

Technical Field

[0001] The invention relates to the technical field of cast-in-place pile construction, and in particular to a hard rock drilling construction system and a construction method for a foundation pit bite pile in a height-restricted area. Background Art

[0002] At present, for cast-in-place pile construction operations in hard rock formations, traditional construction techniques such as impact drilling and rotary drilling are generally used. For cast-in-place pile construction operations in height-restricted areas, the rotary drilling rig is generally modified by lowering its height.

[0003] Although the above construction method can meet the construction height requirements of restricted height areas, the rotary drilling rig itself has low power and torque, so its efficiency is low when drilling in hard rock formations, and the rotary drilling drill bit is easily damaged when facing hard rock. Therefore, there is an urgent need for a system and method that can perform drilling construction in restricted height areas and hard rock formations. Summary of the invention

[0004] In order to overcome the shortcomings of the prior art, the purpose of the present invention is to overcome the difficulties in drilling hard rock cast-in-place piles under environmental conditions in restricted height areas, and to provide a new hard rock drilling hole construction technology, aiming to solve the problems of low construction feasibility, low work efficiency and high cost in the prior art.

[0005] The technical solution adopted by the present invention to solve its technical problem is:

[0006] A hard rock drilling construction system for interlocking piles in a height-restricted area foundation pit comprises a full-casing rotary drilling rig and an improved drilling rig for construction in a height-restricted area and a hard rock layer environment, wherein the hard rock layer comprises an upper soil layer and a lower rock layer, wherein the full-casing rotary drilling rig drives a casing assembly to drill a hole in the upper soil layer, and the improved drilling rig drives a down-the-hole hammer to drill a hole in the lower rock layer; the height of the improved drilling rig is lower than that of the height-restricted area, and the down-the-hole hammer is connected to the improved drilling rig via a drill rod assembly, wherein the drill rod assembly comprises a plurality of short drill rods connected end to end, and the top end of any short drill rod is disconnected and a new short drill rod is added to extend the length of the drill rod assembly.

[0007] By adopting the above technical scheme, an ordinary multifunctional drilling rig is converted into an improved drilling rig whose height is lower than the height of the height restriction zone, and the height of the full casing rotary drilling rig is about 2-3 meters, so that both the full casing rotary drilling rig and the improved drilling rig can perform hole forming work under the height restriction zone, and when breaking the rock of the lower rock layer, the down-the-hole hammer is gradually placed into the hole through the drill rod assembly. Due to the limitation of the height restriction zone, the height of the initial drill rod assembly is definitely not enough to place the down-the-hole hammer at the bottom of the hole. At this time, the top of any short drill rod is disconnected and a new short drill rod is added to lengthen the length of the drill rod assembly. After the length of the lower short drill rod is reached, the drill rod assembly is lengthened again, and this cycle is repeated to place the down-the-hole hammer at the bottom of the hole for breaking the rock;

[0008] The present invention adopts a method of gradually lengthening the drill rod assembly to gradually send the down-the-hole hammer to the bottom of the hole to break the rock, replacing the existing rotary drilling machine, and solving the problems of low efficiency and easy damage of the rotary drilling drill bit caused by using the rotary drilling machine for rock breaking.

[0009] Preferably, one end of the short drill rod is a hexagonal female joint, and the other end is a hexagonal male joint. The hexagonal female joint and the hexagonal male joint are connected by a fixed pin, and the hole wall thickness of the jack of the hexagonal female joint is not less than 5 mm.

[0010] By adopting the above technical solution, the hexagonal female joint of one short drill rod can be connected with the hexagonal sub-joint of another short drill rod, so as to realize the end-to-end connection to form the entire drill rod assembly, the hexagonal sub-joint of the short drill rod at the top of the drill rod assembly is connected with the power head of the improved drilling rig, and the hexagonal female joint of the short drill rod at the bottom of the drill rod assembly is connected with the down-the-hole hammer;

[0011] In addition, the wall thickness of the socket of the hexagonal female connector is not less than 5 mm, which can ensure that the female-female socket connector has sufficient rigidity to effectively transmit the drilling torque.

[0012] Preferably, the length of the short drill rod is 2-6 m, the casing assembly is composed of several sections of casing connected end to end, and the length of each section of the casing is 1 m, 2 m or 3 m.

[0013] By adopting the above technical solution, the length of the short drill rod and the single-section casing is selected according to the height of the height-restricted area. For example, when the height of the height-restricted area is 5m, a short drill rod of 2m or 3m can be used, and a casing with a length of 1m, 2m or 3m can be used.

[0014] Preferably, a dust collection box is provided at the mouth of the hole, and the dust collection box includes a box body formed around the hole, the box body is provided with a rubber dust ring that presses against the down-the-hole hammer or drill rod assembly, and the top of the box body is connected to a water pipe and sprays water to the interior of the upper box body.

[0015] By adopting the above technical solution, during the down-the-hole hammer drilling process, the lower rock layer is broken into debris and blown to the hole mouth by the high-pressure gas generated by the air compressor. When the debris is blown to the hole mouth, it is blocked by the rubber dust ring, and the air flow flows into the box. The dust carried in the upward return air flow is deposited in the box by water mist, which effectively reduces flying dust pollution.

[0016] A method for drilling hard rock of interlocking piles in a foundation pit in a height-restricted area comprises the following steps:

[0017] S1. Prepare improved cranes, full casing rotary drilling rigs and improved drilling rigs;

[0018] S2, moving the full casing rotary drilling rig to a preset position, and using an improved crane to lift the first section of casing with a high-strength alloy cutter head to the full casing rotary drilling rig, and the full casing rotary drilling rig drives the first section of casing to form a hole in the upper soil layer;

[0019] S3, after the full casing rotary drilling rig drives the previous section of casing to be screwed into the hole, the next section of casing is hoisted to the full casing rotary drilling rig by using the improved crane, and the bottom of the next section of casing is fixedly connected to the top of the previous section of casing;

[0020] S4, repeat step S3 until the casing assembly is completely bored in the upper soil layer;

[0021] S5, moving the improved drilling rig to a preset position, and installing the down-the-hole hammer on the improved drilling rig using a drill pipe assembly;

[0022] S6. Drive the down-the-hole hammer deep into the bottom of the hole and drill to the designed depth to break the lower rock layer. When the drill rod assembly is insufficient in length, disconnect the top of any short drill rod and add a new short drill rod to lengthen the length of the drill rod assembly.

[0023] Preferably, in step S1, part of the mast of the crane is dismantled so that the height of the crane is lower than the height of the height restricted area to form an improved crane, and part of the mast of the multi-functional drilling rig is dismantled so that the height of the drilling rig is lower than the height of the height restricted area to form an improved drilling rig.

[0024] Preferably, during the drilling process of the full-casing rotary drilling rig, soil is extracted by means of grabbing soil while rotating and punching, and the casing needs to be drilled ahead by at least 0.5m.

[0025] Preferably, in step S3, the length of each section of the casing is 1m, 2m or 3m; in step S5, the drill rod assembly is composed of a plurality of short drill rods connected end to end, and the length of each section of the short drill rod is 2-6m.

[0026] Preferably, in step S6, the specific steps for lengthening the length of the drill rod assembly are as follows: select a short drill rod as the preceding drill rod, use a U-shaped clamp block to clamp the joint at the top of the preceding drill rod at the hole mouth, disconnect the connection between the preceding drill rod and the power head of the improved drilling rig or the short drill rod above, raise the power head of the improved drilling rig, take a new short drill rod as the subsequent drill rod, the bottom end of the subsequent drill rod is connected to the preceding drill rod, and the top end is connected to the power head of the improved drilling rig or the short drill rod above.

[0027] Preferably, one end of the short drill rod is a hexagonal female joint, and the other end is a hexagonal male joint. The hexagonal female joint and the hexagonal male joint are connected by a fixed pin, and the hole wall thickness of the jack of the hexagonal female joint is not less than 5 mm.

[0028] The beneficial effects of the present invention are:

[0029] 1. Strong adaptability

[0030] The present invention implements a combined process and is suitable for a special construction environment with both a height-restricted area and a hard rock layer. The full-casing rotary drilling rig adopts a casing assembly composed of casings connected one by one to realize the rotary excavation of the upper soil layer, and the improved drilling rig adopts an extendable drill rod assembly to place a down-the-hole hammer into the hole to break the rock of the lower rock layer.

[0031] 2. High efficiency in hard rock drilling

[0032] The present invention adopts an extendable drill rod assembly in combination with a down-the-hole hammer, so that the drill rod assembly can meet the height limit of the height-restricted area and solve the problems of low drilling efficiency and easy damage of the rotary drilling bit caused by the existing rotary drilling rig.

[0033] 3. Good hole quality

[0034] The present invention adopts a combination of "full casing rotary drilling rig + low clearance down-the-hole hammer" drilling method, and the upper soil layer adopts casing assembly wall protection, which effectively improves the stability of the hole wall during the construction process, with less sediment at the bottom of the hole, high hole quality, good pile body appearance quality, and relatively easy control of settlement and deformation during construction;

[0035] 4. No flying dust or slight flying dust in the construction environment

[0036] The present invention arranges a dust collection box at the hole mouth, and in the process of rock breaking by the down-the-hole hammer, the dust carried in the upward return airflow is deposited in the box through water mist, thereby effectively reducing flying dust pollution. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0038] Figure 1 It is a schematic diagram of the steps of converting a crane into an improved crane in the present invention;

[0039] Figure 2 It is a structural schematic diagram of the improved drilling rig in the present invention;

[0040] Figure 3 It is a schematic diagram of extending the sleeve assembly in the present invention;

[0041] Figure 4 It is a schematic diagram of extending the drill rod assembly in the present invention;

[0042] Figure 5 This is a schematic diagram of the structure of the mother-child hexagonal joint of the present invention;

[0043] Figure 6 It is a structural diagram of the dust collection box in the drilling construction system;

[0044] Figure 7 It is a flowchart of the drilling construction method;

[0045] Figure 8 This is a construction diagram of the drilling construction method.

[0046] The descriptions of the reference numerals in the figures are as follows:

[0047] 1. Improved crane;

[0048] 2. Improved drilling rig; 201. Power head;

[0049] 3. Casing assembly; 301. Casing; 302. Screw;

[0050] 4. Drill rod assembly; 401. short drill rod; 402. preceding drill rod; 403. succeeding drill rod; 404. U-shaped block; 405. hexagonal male connector; 406. hexagonal female connector;

[0051] 5. Down-the-hole hammer;

[0052] 6. Dust-proof collection box; 601. Box body; 602. Rubber dust-proof ring. DETAILED DESCRIPTION

[0053] The following will clearly and completely describe the concept, specific structure and technical effects of the present invention in combination with the embodiments and drawings, so as to fully understand the purpose, characteristics and effects of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, other embodiments obtained by technicians in this field without creative work are all within the scope of protection of the present invention. In addition, all the connection / connection relationships involved in the patent do not refer to the direct connection of components, but refer to the formation of a better connection structure by adding or reducing connection accessories according to the specific implementation situation. The various technical features in the invention can be combined interchangeably without conflicting with each other.

[0054] A hard rock drilling construction system for interlocking piles in a height-restricted area foundation pit comprises an improved crane 1, a full-casing rotary drilling rig and an improved drilling rig 2 for construction in a height-restricted area and a hard rock layer. The improved crane 1 is used to lift a casing 301 to the full-casing rotary drilling rig in the height-restricted area. The hard rock layer comprises an upper soil layer and a lower rock layer.

[0055] like Figure 1 As shown, a part of the mast of a common crane is dismantled so that the height of the crane is lower than the height of the height-restricted area to form an improved crane 1.

[0056] like Figure 2As shown, part of the mast of the multifunctional drilling rig is dismantled so that the height of the multifunctional drilling rig is lower than the height of the height-restricted area to form an improved drilling rig 2. The original mast height of the multifunctional drilling rig is 28m, and the height of the modified improved drilling rig 2 is 8m. The remaining structure of the improved drilling rig 2 remains unchanged with the original multifunctional drilling rig, and is mainly composed of a chassis, a mast, a follower frame, a power head 201, a rotating rod and a fixed frame.

[0057] like Figure 3 As shown, the full casing rotary drilling rig drives the casing assembly 3 to drill a hole in the upper soil layer. The casing assembly 3 is composed of a plurality of casings 301 connected end to end. After the previous casing 301 is screwed into the hole by the full casing rotary drilling rig, a new casing 301 is taken and installed on the top of the previous casing 301 to lengthen the overall length of the casing assembly 3. The sleeves are connected end to end by opening screw holes and passing screw rods 302 through the screw holes.

[0058] The improved drilling rig 2 is connected to the down-the-hole hammer 5 through the drill rod assembly 4, and drives the down-the-hole hammer 5 to drill a hole in the lower rock layer. The height of the improved drilling rig 2 is lower than the height of the height-restricted area. The drill rod assembly 4 is composed of a number of short drill rods 401 connected end to end. The top end of any short drill rod 401 is disconnected and a new short drill rod 401 is added to lengthen the length of the drill rod assembly 4.

[0059] The specific steps for lengthening the length of the drill rod assembly 4 are as follows: select a short drill rod 401 as the preceding drill rod 402, use a U-shaped clamp 404 to clamp the joint at the top of the preceding drill rod 402 at the hole mouth, disconnect the connection between the preceding drill rod 402 and the power head 201 of the improved drilling rig 2 or the short drill rod 401 above, raise the power head 201 of the improved drilling rig 2, take a new short drill rod 401 as the subsequent drill rod 403, the bottom end of the subsequent drill rod 403 is connected to the preceding drill rod 402, and the top end thereof is connected to the power head 201 of the improved drilling rig 2 or the short drill rod 401 above.

[0060] The specific working principle for solving the technical problem is as follows: an ordinary multi-functional drilling rig is converted into an improved drilling rig 2 whose height is lower than the height of the height restriction zone, and the height of the full casing rotary drilling rig is about 2-3 meters, so that both the full casing rotary drilling rig and the improved drilling rig 2 can perform hole-forming work under the height restriction zone; when the improved drilling rig 2 is breaking the rock of the lower rock layer, the down-the-hole hammer 5 is gradually placed into the hole through the drill rod assembly 4. Due to the limitation of the height restriction zone, the initial height of the drill rod assembly 4 is definitely not enough to place the down-the-hole hammer 5 at the bottom of the hole. At this time, the top of any short drill rod 401 is disconnected and a new short drill rod 401 is added to lengthen the length of the drill rod assembly 4. After the down-the-hole hammer is lowered to the depth of a short drill rod 401, the drill rod assembly 4 is lengthened again, and this cycle is repeated to place the down-the-hole hammer 5 at the bottom of the hole for rock breaking.

[0061] The present invention adopts a method of gradually lengthening the drill rod assembly 4 to gradually send the down-the-hole hammer 5 to the bottom of the hole for rock breaking, replacing the existing rotary drilling machine, and solving the problems of low efficiency and easy damage of the rotary drilling drill bit caused by using the rotary drilling machine for rock breaking.

[0062] In order to achieve a detachable connection relationship between the short drill rods 401 and the short drill rods 401 or between the short drill rods 401 and the power head 201 of the improved drilling rig 2, the present invention further defines the short drill rods 401 as follows.

[0063] One end of the short drill rod 401 is a hexagonal female connector 406, and the other end is a hexagonal male connector 405. The hexagonal female connector 406 and the hexagonal male connector 405 are connected by a fixed pin.

[0064] The hexagonal female joint 406 of one short drill rod 401 can be connected to the hexagonal sub-joint 405 of another short drill rod 401, so as to achieve end-to-end connection to form the entire drill rod assembly 4, the hexagonal sub-joint 405 of the short drill rod 401 at the top of the drill rod assembly 4 is connected to the power head 201 of the improved drilling rig 2, and the hexagonal female joint 406 of the short drill rod 401 at the bottom of the drill rod assembly 4 is connected to the down-the-hole hammer 5.

[0065] Furthermore, the wall thickness of the jack of the hexagonal female connector 406 is not less than 5 mm, which can ensure that the female-female socket connector has sufficient rigidity to effectively transmit the drilling torque.

[0066] The length of the short drill rod 401 is 2-6m, and the casing assembly 3 is composed of several sections of casing 301 connected end to end, and the length of each section of casing 301 is 1m, 2m or 3m; the length of the short drill rod 401 and the single section of casing 301 is selected according to the height of the height restricted area. For example, when the height of the height restricted area is 5m, a short drill rod 401 of 2m or 3m can be used, and a casing 301 with a length of 1m, 2m or 3m can be used.

[0067] When the down-the-hole hammer 5 is performing rock breaking work, an air duct connected to an air compressor is placed into the bottom of the hole to blow out the rock dust at the bottom of the hole, causing excessive flying dust in the construction environment.

[0068] like Figure 6 As shown, in order to solve this problem, the present invention provides a dust collection box 6 at the mouth of the hole, and the dust collection box 6 includes a box body 601 formed around the hole, and the box body 601 is provided with a rubber dust ring 602 pressed against the down-the-hole hammer 5 or the drill rod assembly 4. The top of the box body 601 is connected to a water pipe and water is sprayed into the box body 601.

[0069] During the drilling process of the down-the-hole hammer 5, the lower rock layer is broken into debris and blown to the hole mouth by the high-pressure gas generated by the air compressor. When the debris is blown to the hole mouth, it is blocked by the rubber dust ring 602, and the air flow flows into the box 601. The dust carried in the upward return air flow is deposited in the water mist and remains in the box 601, which effectively reduces the flying dust pollution.

[0070] exist Figure 6 In the figure, the box body 601 is divided into an upper box and a lower box. A filter screen capable of filtering water is used at the connection between the upper box and the lower box to allow excess water in the upper box to flow into the lower box and be discharged.

[0071] In addition, the present invention also provides a construction method corresponding to the above-mentioned construction system as follows.

[0072] A construction method for hard rock drilling of interlocking piles in a foundation pit in a height-restricted area, such as Figure 7 and Figure 8 As shown, the following steps are included:

[0073] S1, prepare improved crane 1, full casing rotary drilling rig and improved drilling rig 2;

[0074] The modification method of the improved crane 1 and the improved drilling rig 2 is: dismantle part of the mast of the crane so that the height of the crane is lower than the height of the height-restricted area to form the improved crane 1, and dismantle part of the mast of the multi-functional drilling rig so that the height of the drilling rig is lower than the height of the height-restricted area to form the improved drilling rig 2.

[0075] S2, moving the full casing rotary drilling rig to a preset position, and using the improved crane 1 to lift the first section of casing 301 with a high-strength alloy cutter head to the full casing rotary drilling rig, and the full casing rotary drilling rig drives the first section of casing 301 to form a hole in the upper soil layer;

[0076] Step S2 is specifically as follows: the first section of casing 301 is lifted by the improved crane 1 to install the first section of casing 301; the first section of casing 301 is provided with a high-strength alloy cutter head, and the construction effect of the first section of casing 301 is the main factor affecting the verticality of the pile foundation, so it is necessary to ensure that it is as vertical as possible, and during the downward pressing process, the verticality of the casing 301 is detected from the X and Y axis directions using a measuring hammer in conjunction with a theodolite (total station). If deflection occurs, the outrigger cylinder of the full-rotation drilling rig can be adjusted to ensure that the casing 301 is vertical (the adjustment must be followed by detection with a theodolite).

[0077] S3, after the full casing rotary drilling rig drives the previous section of casing 301 to be screwed into the hole, the improved crane 1 is used to lift the next section of casing 301 to the full casing rotary drilling rig, and the bottom of the next section of casing 301 is fixedly connected to the top of the previous section of casing 301.

[0078] In step S3 , the length of each section of casing 301 is 1 m, 2 m or 3 m.

[0079] When the full-casing rotary drilling rig is about to drill into the lower rock formation, the casing 301 of appropriate length should be reasonably installed to avoid the casing assembly 3 being insufficient in length or exposed too much when the casing 301 reaches the lower rock formation, which will cause inconvenience in subsequent work. For example, when the full-casing rotary drilling rig drills to the point where the distance between the lower end of the casing assembly 3 and the lower rock formation is 10m, three 3m casings 301 and one 1m casing 301 can be selected for subsequent drilling work.

[0080] In steps S2 and S3, during the drilling process of the full-casing rotary drilling rig, soil is taken by rotating and punching at the same time, and the casing 301 needs to be drilled ahead by at least 0.5m.

[0081] S4, repeat step S3 until the casing assembly 3 is completely bored in the upper soil layer.

[0082] At this point, the upper soil layer has been completely drilled by the full-casing rotary drilling rig, and the casing assembly 3 has been installed at the hole wall. The subsequent operation will break the rock and drill the hole in the lower rock layer.

[0083] S5, moving the improved drilling rig 2 to a preset position, and installing the down-the-hole hammer 5 to the improved drilling rig 2 using the drill rod assembly 4.

[0084] In step S5, the drill rod assembly 4 is composed of a number of short drill rods 401 connected end to end, the length of each section of the short drill rod 401 is 2-6m, one end of the short drill rod 401 is a hexagonal female joint 406, and the other end is a hexagonal male joint 405. The hexagonal female joint 406 and the hexagonal male joint 405 are connected by a fixed pin, and the hole wall thickness of the plug hole of the hexagonal female joint 406 is not less than 5mm.

[0085] S6, driving the down-the-hole hammer 5 deep into the bottom of the hole to break the rock in the lower layer to the designed depth. When the drill rod assembly 4 is not long enough, disconnect the top of any short drill rod 401 and connect a new short drill rod 401 to lengthen the length of the drill rod assembly 4;

[0086] In step S6, the specific steps for lengthening the length of the drill rod assembly 4 are as follows: select a short drill rod 401 as the preceding drill rod 402, use the U-shaped clamping block 404 to clamp the joint at the top of the preceding drill rod 402 at the hole mouth, disconnect the connection between the preceding drill rod 402 and the power head 201 of the improved drilling rig 2 or the short drill rod 401 above, raise the power head 201 of the improved drilling rig 2, take a new short drill rod 401 as the subsequent drill rod 403, the bottom end of the subsequent drill rod 403 is connected to the preceding drill rod 402, and the top end thereof is connected to the power head 201 of the improved drilling rig 2 or the short drill rod 401 above.

[0087] After drilling a hole in the lower rock stratum to the designed depth, lift the power head 201 of the improved drilling rig 2 to the top of the height limit area, then use the U-shaped clamp 404 to clamp the top of the short drill rod 401 near the hole mouth, remove the short drill rod 401 between the short drill rod 401 and the power head 201, and connect the lower end of the power head 201 to the top of the short drill rod 401 at the hole mouth, then lift the power head 201 of the improved drilling rig 2 to the top of the height limit area, repeat the operation, and remove the down-the-hole hammer 5 from the hole.

[0088] After the upper soil layer and the lower rock layer have been bored, the hard rock drilling construction process in the height-restricted area is completed, and then the installation of the steel cage and the pouring conduit are carried out, including the following:

[0089] S7. Place steel cage and perfusion catheter

[0090] 1. According to the actual situation on site, the construction method of segmented lifting into the hole is adopted, and the connection of each section of the steel cage is realized through the sleeve connection at the hole mouth;

[0091] 2. After the steel cage is connected, align it with the hole during hoisting, hoist it straight and steady, and slowly lower it into place;

[0092] 3. For concrete pouring conduit, choose a 300mm diameter conduit. Check each section of the conduit before placing it. A sealing water pressure test is required when using it for the first time. Add sealing rings and apply butter to the conduit connection parts to ensure a reliable seal. The bottom of the conduit should be 300 to 500mm away from the bottom of the hole. When lowering the conduit, adjust the length of the conduit.

[0093] S8, pouring concrete and pulling out the casing 301

[0094] 1. After the steel cage and the pouring conduit are placed, the bottom sediment of the hole is measured. If it meets the requirements, underwater concrete pouring is carried out; if the thickness of the bottom sediment exceeds the standard, the air lift reverse circulation secondary hole cleaning is adopted;

[0095] 2. The pile body concrete adopts C35 underwater commercial concrete with a slump of 180-220mm. This project adopts the hopper pouring method for concrete pouring. The initial pouring is to ensure that the concrete can block the bottom of the hole, and 2-3m3 of concrete is poured at one time. ;

[0096] 3. This project uses a vibration clamp to pull out the casing 301; during the concrete pouring process, the casing 301 and the conduit should be pulled out frequently according to the pouring height to prevent the casing 301 and the conduit from solidifying in the concrete. Strict control should be exercised to prevent the casing 301 and the conduit from being pulled out too quickly and exposed to the concrete surface, causing the risk of broken piles. The bottom of the casing 301 and the conduit should be kept 2 to 4 meters below the concrete surface, and the maximum should not be greater than 6 meters;

[0097] 4. During the concrete pouring process, lift the hopper and the guide tube up and down from time to time so that the concrete in the pipe can smoothly flow into the hole, until the concrete is poured to the designed pile top elevation and exceeds the designed pile top elevation by 0.8m to 1.0m.

[0098] The above is a specific description of the preferred implementation of the present invention, but the invention is not limited to the embodiments. Those skilled in the art can make various equivalent modifications or substitutions without violating the spirit of the present invention. These equivalent modifications or substitutions are all included in the scope defined by the claims of this application.

Claims

1. A construction system for hard rock drilling of interlocking piles in foundation pits in height-restricted areas, characterized in that: It includes a full-casing rotary drilling rig and an improved drilling rig for construction in a height-restricted area and a hard rock layer environment, wherein the hard rock layer includes an upper soil layer and a lower rock layer, the full-casing rotary drilling rig drives the casing assembly to form a hole in the upper soil layer, and the improved drilling rig drives a down-the-hole hammer to form a hole in the lower rock layer; The height of the improved drilling rig is lower than the height of the height-restricted area, and it is connected to the down-the-hole hammer through a drill rod assembly, wherein the drill rod assembly is composed of a plurality of short drill rods connected end to end, and the top end of any short drill rod is disconnected and a new short drill rod is added to lengthen the length of the drill rod assembly; One end of the short drill rod is a hexagonal female joint, and the other end is a hexagonal male joint. The hexagonal female joint and the hexagonal male joint are connected by a fixed pin, and the wall thickness of the jack of the hexagonal female joint is not less than 5 mm; A dust collection box is provided at the opening of the hole, and the dust collection box includes a box body formed around the hole. The box body is provided with a rubber dust ring pressed against the down-the-hole hammer or drill rod assembly. The top of the box body is connected to a water pipe and sprays water to the interior of the upper box body.

2. The hard rock drilling construction system for the foundation pit with interlocking piles in the height-restricted area according to claim 1 is characterized in that: The length of the short drill rod is 2-6m, and the casing assembly is composed of a plurality of casing sections connected end to end, and the length of each casing section is 1m, 2m or 3m.

3. A method for hard rock drilling of interlocking piles in a foundation pit in a height-restricted area, characterized in that: The following steps are involved: S1. Prepare improved cranes, full casing rotary drilling rigs and improved drilling rigs; S2, moving the full casing rotary drilling rig to a preset position, and using an improved crane to lift the first section of casing with a high-strength alloy cutter head to the full casing rotary drilling rig, and the full casing rotary drilling rig drives the first section of casing to form a hole in the upper soil layer; S3, after the full casing rotary drilling rig drives the previous section of casing to be screwed into the hole, the next section of casing is hoisted to the full casing rotary drilling rig by using the improved crane, and the bottom of the next section of casing is fixedly connected to the top of the previous section of casing; S4, repeat step S3 until the casing assembly is completely bored in the upper soil layer; S5, moving the improved drilling rig to a preset position, and installing the down-the-hole hammer on the improved drilling rig using a drill pipe assembly; S6. Drive the down-the-hole hammer deep into the bottom of the hole to break the rock in the lower layer and drill to the designed depth. When the drill rod assembly is not long enough, disconnect the top of any short drill rod and connect a new short drill rod to lengthen the length of the drill rod assembly. In step S1, a part of the mast of the crane is dismantled so that the height of the crane is lower than the height of the height-restricted area to form an improved crane, and a part of the mast of the multi-functional drilling rig is dismantled so that the height of the drilling rig is lower than the height of the height-restricted area to form an improved drilling rig; In step S6, the specific steps of lengthening the length of the drill rod assembly are as follows: select a short drill rod as the preceding drill rod, use a U-shaped clamping block to clamp the joint at the top of the preceding drill rod at the hole mouth, disconnect the preceding drill rod from the power head of the improved drilling rig or the short drill rod above, raise the power head of the improved drilling rig, take a new short drill rod as the succeeding drill rod, connect the bottom end of the succeeding drill rod to the preceding drill rod, and connect the top end of the succeeding drill rod to the power head of the improved drilling rig or the short drill rod above; One end of the short drill rod is a hexagonal female joint, and the other end is a hexagonal male joint. The hexagonal female joint and the hexagonal male joint are connected by a fixed pin, and the hole wall thickness of the jack of the hexagonal female joint is not less than 5mm.

4. The method for hard rock drilling of interlocking piles in a foundation pit in a height-restricted area according to claim 3 is characterized in that: During the drilling process of the full-casing rotary drilling rig, soil is taken by rotating and flushing at the same time, and the casing needs to be drilled ahead by at least 0.5m.

5. The method for hard rock drilling of interlocking piles in a foundation pit in a height-restricted area according to claim 3 is characterized in that: In step S3, the length of each section of the casing is 1m, 2m or 3m; in step S5, the drill rod assembly is composed of a plurality of short drill rods connected end to end, and the length of each section of the short drill rod is 2-6m.

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