Sand layer geology pile foundation hole bottom grouting device and construction method

Abstract

A sand layer geology pile foundation hole bottom grouting device and construction method, the device comprises: a reinforcement cage, a plurality of water bags, a plurality of fixed guide mechanisms, a plurality of water injection switch valves. By installing a plurality of fixed guide mechanisms in the reinforcement cage, the setting direction of the plurality of water bags is consistent with the reinforcement cage; by a plurality of water injection switch valves, the plurality of water bags are watered, and after the watering is completed, the surface of the plurality of water bags is smeared with machine oil for subsequent demolding and taking out; the reinforcement cage with the plurality of water bags is installed into the drilled pile hole, and the pile foundation is concreted; after the pile foundation concrete reaches the design age, the plurality of water bags are taken out after being drained, forming a plurality of holes; finally, the plurality of holes are completed grouting. Compared with the traditional grouting pipe construction method through pre-embedded steel pipes, the water bag is recycled in the embodiment of the application, steel is saved, quality problems caused by the blockage of the grouting pipe and the inability to grout are avoided, and the construction progress is also accelerated.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of building construction, in particular to a sand layer geological pile foundation hole bottom grouting device and construction method. BACKGROUND

[0002] Pile foundation is the main means and form of building deep foundation, and bored pile can be made into large size and drilled into deep soil layer, which can provide large bearing capacity and other advantages, and has been widely used in the field of building foundation. Due to the inherent defects of pile foundation hole forming process, especially in the coastal sand layer geology, the thickness of pile bottom sediment after hole forming is difficult to meet the design and specification requirements, so the domestic foundation treatment grouting technology is introduced into the pile foundation, and the measures of implementing pressure grouting on the pile end, that is, the pile foundation post-grouting technology. The pile foundation post-grouting technology is to use high-pressure grouting pump to pressurize and inject cement slurry to solidify the hole bottom sediment after the pile reaches a certain strength, so as to eliminate the inherent defects of traditional process and improve the bearing capacity of the pile.

[0003] The conventional pile foundation post-grouting technology is to pre-bury a seamless steel pipe, and after the pile body concrete reaches a certain strength, the hole bottom grouting is carried out through the pre-buried steel pipe. However, in the actual construction process, a large amount of concrete cement slurry often enters the pre-buried seamless steel pipe when the pile foundation is underwater concrete pouring, which blocks the steel pipe, resulting in that the post-grouting cannot be carried out through the pre-buried steel pipe, the hole bottom sediment cannot be solidified, the pile foundation quality is affected, the pile foundation bearing capacity cannot meet the design requirements, the installation operation is difficult, and the pre-buried steel pipe also has the disadvantages of high cost, long construction period and the like. SUMMARY

[0004] The present application aims to solve at least one of the technical problems existing in the prior art. To this end, the present application provides a sand layer geological pile foundation hole bottom grouting device, which solves the technical problems of difficult installation operation and difficult to meet the technical quality requirements of the current pre-buried seamless steel pipe pile foundation post-grouting technology.

[0005] The present application also provides a sand layer geological pile foundation hole bottom grouting construction method.

[0006] The sand layer geological pile foundation hole bottom grouting device according to the first aspect of the present application comprises:

[0007] A steel reinforcement cage;

[0008] A plurality of water bags, each of which comprises a water storage part and a water injection part, the water storage part is arranged along the axial direction of the steel reinforcement cage, and the water injection part is located at the top of the water bag;

[0009] A plurality of fixed guide mechanisms are arranged on the inner side of the steel reinforcement cage and connected with the main reinforcement of the steel reinforcement cage, and the plurality of fixed guide mechanisms are used together to limit the positions of the plurality of water bags in the steel reinforcement cage.

[0010] A plurality of water injection switch valves are connected to the plurality of water injection parts one by one.

[0011] The sand layer geology pile foundation hole bottom grouting device has at least the following technical effects: the plurality of water bags are arranged in the same direction as the reinforcement cage by installing a plurality of fixed guide mechanisms in the reinforcement cage; the plurality of water bags are injected with water by the high-pressure water injection equipment through the plurality of water injection switch valves, and the surfaces of the plurality of water bags are smeared with machine oil after the water injection is completed, so that the plurality of water bags can be demolded and taken out subsequently; the reinforcement cage in which the plurality of water bags are placed is installed into the drilled pile hole, and the pile foundation is poured with concrete; after the pile foundation concrete reaches the design age, the plurality of water bags are taken out after being drained through the plurality of water injection switch valves, and a plurality of channels are formed; and finally, the plurality of channels are grouted. Compared with the traditional grouting pipe construction method by pre-buried steel pipes, the water bags are recycled in the embodiment of the present application, steel materials are saved, quality problems caused by the blockage of the grouting pipe and the failure of grouting are avoided, and the construction progress is also accelerated.

[0012] According to some embodiments of the present application, the plurality of fixed guide mechanisms are evenly grouped into a plurality of fixed guide units according to the number, and the plurality of fixed guide units are arranged on the inner side of the reinforcement cage in a vertical direction, each fixed guide mechanism in each fixed guide unit is located on the same horizontal plane and is arranged in a ring shape at equal intervals.

[0013] According to some embodiments of the present application, the plurality of fixed guide mechanisms are a plurality of iron rings with an inner diameter of 30 mm, each iron ring is made of a steel bar with an inner diameter of 6 mm, and the plurality of iron rings are welded to the plurality of main reinforcement bars.

[0014] According to some embodiments of the present application, the plurality of water bags are a plurality of cylinders with a diameter of 20 mm.

[0015] According to some embodiments of the present application, each water bag adopts a polyurethane high molecular film structure.

[0016] According to some embodiments of the present application, the internal water injection pressure of each water bag is greater than the concrete pouring pressure.

[0017] According to some embodiments of the present application, the plurality of water injection switch valves are arranged at the top of the plurality of water injection parts.

[0018] The sand layer geology pile foundation hole bottom grouting construction method according to the second aspect of the present application comprises the following steps:

[0019] Excavating a water storage tank and a sedimentation tank;

[0020] Measuring and laying out the pile foundation and burying a steel casing;

[0021] Drilling is carried out on the strata, and the bottom grouting device for sandy geological pile foundation as described in any of the embodiments of the first aspect of the present invention is installed into the drilled pile hole.

[0022] Concrete is poured into the pile foundation;

[0023] Grouting is performed at the bottom of the hole.

[0024] The bottom grouting construction method for sandy geological pile foundations according to embodiments of the present invention has at least the following technical effects: A drainage system is formed by excavating a water storage tank and a sedimentation tank, ensuring the recycling of water resources; the piles are protected by burying steel casings, preventing hole collapse and avoiding impacts on construction progress and safety; the bottom grouting device for sandy geological pile foundations according to embodiments of the present invention is installed into the drilled pile holes, and concrete is poured into the pile foundation; after the pile foundation concrete reaches the design age, multiple water-filled valves are used to release water from multiple water-filled bladders, which are then removed to form multiple channels; finally, grouting is performed on these multiple channels. Compared to the traditional grouting pipe construction method using pre-embedded steel pipes, the present invention recycles and reuses water-filled bladders, saving steel, avoiding quality problems caused by grouting blockage, and also accelerating the construction progress.

[0025] According to some embodiments of the present invention, the bottom grouting device for sandy geological pile foundation holes is obtained by the following steps:

[0026] Fabricate a steel cage, which is composed of multiple main bars and multiple stirrups;

[0027] Multiple iron rings with an inner diameter of 30 mm are fabricated, each of which is composed of multiple steel bars with an inner diameter of 6 mm. The multiple iron rings are welded to the multiple main bars on the inner side of the steel cage.

[0028] A water bladder is selected, which is a cylinder with a diameter of 20 mm and a polyurethane polymer membrane structure.

[0029] The water tanks are filled with water using an external high-pressure water injection device and multiple water injection switch valves until the water storage compartments of the multiple water tanks are full, at which point the water injection stops.

[0030] Apply machine oil to the outer surface of the multiple water bladders and place them in the multiple iron rings.

[0031] According to some embodiments of the present invention, the grouting at the bottom of the hole includes the following steps:

[0032] Water is released from the multiple water bladders through the multiple water injection switch valves;

[0033] Multiple water bags are removed from the bottom grouting device of the sandy geological pile foundation hole;

[0034] cleaning the plurality of channels formed by the pile foundation after the plurality of water bags are taken out;

[0035] bottom grouting of the plurality of channels.

[0036] Additional aspects and advantages of the present application will be in part apparent and in part pointed out below in the description of embodiments of the present application. BRIEF DESCRIPTION OF DRAWINGS

[0037] The above and / or additional aspects and advantages of the present application will become apparent and be readily appreciated from the following description, including the appended drawings, wherein:

[0038] Figure 1 is a structural schematic diagram of a sand layer geological pile foundation bottom grouting device according to an embodiment of the present application;

[0039] Figure 2 is a structural schematic diagram of a water bag and a water injection switch valve according to an embodiment of the present application;

[0040] Figure 3 is a top view of a reinforcement cage, a water bag and a fixing guide mechanism according to an embodiment of the present application;

[0041] Figure 4 is a flow chart of a sand layer geological pile foundation bottom grouting construction method according to an embodiment of the present application.

[0042] REFERENCE NUMERALS:

[0043] reinforcement cage 100, main reinforcement 110, stirrup 120,

[0044] water bag 200, water storage part 210, water injection part 220,

[0045] fixing guide mechanism 300,

[0046] water injection switch valve 400. DETAILED DESCRIPTION

[0047] Embodiments of the present application are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals represent the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by reference to the accompanying drawings are exemplary and are for the purpose of explanation only, and are not to be understood as limiting the present application.

[0048] In the description of the present application, it should be understood that the orientation description, such as the orientation or positional relationship indicated by the upper, lower, front, rear, left, right and the like, is based on the orientation or positional relationship shown in the drawings, and is only for the purpose of facilitating the description of the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation of the present application.

[0049] In the description of the present application, the meaning of multiple is more than two. If the first, second is described, it is only for the purpose of distinguishing technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features or implicitly indicating the order of indicated technical features.

[0050] In the description of the present application, unless otherwise explicitly limited, the words such as setting, installing, connecting, disconnecting and the like should be broadly understood, and the person skilled in the art can reasonably determine the specific meaning of the above words in the present application in combination with the specific content of the technical scheme.

[0051] The following refers to Figures 1 to 4 The sand layer geotechnical pile foundation hole bottom grouting device according to the first aspect of the present application is described.

[0052] The sand layer geotechnical pile foundation hole bottom grouting device of the embodiment of the present application comprises:

[0053] The steel reinforcement cage 100;

[0054] A plurality of water bags 200, each water bag 200 comprising a water storage part 210 and a water injection part 220, the water storage part 210 being arranged along the axial direction of the steel reinforcement cage 100, and the water injection part 220 being located at the top of the water bag 200;

[0055] A plurality of fixed guide mechanisms 300 are arranged on the inner side of the steel reinforcement cage 100 and are connected with the main reinforcement 110 of the steel reinforcement cage 100, and the plurality of fixed guide mechanisms 300 are used together to limit the position of the plurality of water bags 200 in the steel reinforcement cage 100;

[0056] A plurality of water injection on-off valves 400 are connected one by one with the plurality of water injection parts 220.

[0057] Reference is made to Figures 1 to 3, the steel cage 100 is long-cylindrical in appearance as a whole, a plurality of main reinforcements 110 are parallel to each other and form a cylinder ring, and a plurality of stirrups 120 are wound on the cylinder ring formed by the plurality of main reinforcements 110, so that the steel cage 100 is finally formed to be stable in structure; the upper end part of the main reinforcement 110 is a bent part, which will be exposed above the ground surface when the steel cage 100 is used; a plurality of fixed guide mechanisms 300 are uniformly distributed on the plurality of main reinforcements 110, so as to ensure that the plurality of water bags 200 are arranged in a vertical direction and consistent with the arrangement direction of the steel cage 100; when the sand layer geological pile foundation hole bottom grouting device of the embodiment of the present application is used, the main body of the steel cage 100 and the water storage part 210 of the plurality of water bags 200 will be below the ground surface of the sand layer geology, and the bent part of the steel cage 100 and the water injection part 220 of the plurality of water bags 200 will be above the ground surface of the sand layer geology, so as to facilitate the relevant operation of the construction personnel to place or take out the steel cage 100 and the water bag 200; each water injection switch valve 400 is arranged on the water injection part 220 of each water bag 200, so as to facilitate the construction personnel to inject water and drain water for the water bag 200.

[0058] Specifically, the construction body using the sand layer geological pile foundation hole bottom grouting device of the embodiment of the present application is as follows: drilling the sand layer geology under the ground surface, installing the sand layer geological pile foundation hole bottom grouting device of the embodiment of the present application to the drilled pile hole, and injecting water for the plurality of water bags 200 through the plurality of water injection switch valves 400 before and after the device is installed to the pile hole, and the surface of the water bag 200 needs to be smeared with machine oil in advance before the plurality of water bags 200 are placed in the steel cage 100. After the pile foundation concrete reaches the design age, i.e. after the concrete is solidified, the plurality of water bags 200 are drained and taken out from the device to form a plurality of channels, and finally the plurality of channels are grouted, thereby completing the construction.

[0059] According to the sand layer geological pile foundation hole bottom grouting device of the embodiment of the present application, the arrangement direction of the plurality of water bags 200 is consistent with the steel cage 100 by installing the plurality of fixed guide mechanisms 300 in the steel cage 100; the plurality of water bags 200 are injected with water by the plurality of water injection switch valves 400 using the high-pressure water injection equipment, the surface of the plurality of water bags 200 is smeared with machine oil after the water injection is completed, so as to facilitate the subsequent demolding and taking out of the plurality of water bags 200; the steel cage 100 in which the plurality of water bags 200 are placed is installed to the drilled pile hole, and the pile foundation is poured with concrete; when the pile foundation concrete reaches the design age, the plurality of water bags 200 are taken out after being drained by the plurality of water injection switch valves 400, thereby forming a plurality of channels; finally, the plurality of channels are grouted. Compared with the traditional grouting pipe construction method by pre-buried steel pipes, the embodiment of the present application recycles the water bags 200, saves steel materials, avoids the quality problems caused by the blockage of the grouting pipe and the inability to grout, and also speeds up the construction progress.

[0060] In some embodiments of the present application, the plurality of fixed guiding mechanisms 300 are evenly grouped into a plurality of fixed guiding units according to the number, and the plurality of fixed guiding units are arranged at intervals in the vertical direction on the inner side of the reinforcement cage 100. Each fixed guiding mechanism 300 in each fixed guiding unit is located on the same horizontal plane and is arranged at equal intervals in a ring shape.

[0061] Referring to Figure 3 , for example, in a top view, one fixed guiding unit on the inner side of the reinforcement cage 100 is composed of two fixed guiding mechanisms 300 (in some embodiments, more fixed guiding mechanisms 300 can be used to form a fixed guiding unit), and the two fixed guiding mechanisms 300 are arranged in a ring shape and symmetrically. Figure 1 , along the vertical direction of the reinforcement cage 100, a plurality of fixed guiding units are arranged at intervals, and the fixed guiding mechanisms 300 in each fixed guiding unit are on the same plane. Therefore, the plurality of fixed guiding mechanisms 300 are regularly arranged on the inner side of the reinforcement cage 100 to ensure the stability of the fixed guiding effect on the plurality of water bags 200.

[0062] In some embodiments of the present application, the plurality of fixed guiding mechanisms 300 are a plurality of iron rings with an inner diameter of 30 mm, each iron ring is made of steel reinforcement with an inner diameter of 6 mm, and the plurality of iron rings are welded to the plurality of main reinforcements 110.

[0063] Specifically, the fixed guiding mechanism 300 adopts an iron ring to ensure good fixing effect. In some embodiments, alloys, stainless steel, and composite materials can also be used to make the fixed guiding mechanism 300; at the same time, on the basis of the ring shape, the fixed guiding mechanism 300 can also be adjusted to a ring buckle, which can further facilitate the placement of the water bag 200 in the reinforcement cage 100.

[0064] In some embodiments of the present application, the plurality of water bags 200 are a plurality of cylinders with a diameter of 20 mm.

[0065] Specifically, referring to Figure 2 , the water bag 200 can maintain the appearance of a cylinder after being shaped after being filled with water, but due to differences in material, when the water bag 200 is not filled with water, if the water bag 200 is made of a material with relatively stronger hardness, the water bag 200 can itself maintain a cylindrical shape; and if the water bag 200 is made of a material with relatively weaker hardness, the water bag 200 may not be able to present a clear cylindrical shape in appearance.

[0066] In some embodiments of the present application, each water bag 200 adopts a polyurethane high molecular film structure.

[0067] Specifically, the polyurethane high molecular film structure has the advantages of thermoplasticity, high strength, large elongation, good resilience, wear resistance, oil resistance, aging resistance, low temperature resistance, etc., and thus meets the relevant index requirements of the water bag 200 in the construction process.

[0068] In some embodiments of the present application, the internal pressure of each water bag 200 subjected to water injection is greater than the concrete pouring pressure.

[0069] Specifically, the conventional method is to use a seamless steel pipe to form the hole, and the hardness of the seamless steel pipe is obviously stronger than the hardness of the concrete structure, so as to ensure the formation of the hole. Similarly, for the water bag 200 used in the embodiments of the present application, the hardness after water injection also needs to be stronger than the hardness of the concrete structure, which is specifically embodied in that the internal pressure of the water bag 200 subjected to water injection should be greater than the concrete pouring pressure, so as to ensure the formation of the hole.

[0070] In some embodiments of the present application, a plurality of water injection on-off valves 400 are arranged at the top ends of the plurality of water injection parts 220.

[0071] Specifically, referring to Figure 2 Arranging the water injection on-off valve 400 at the top end of the water injection part 220 of the water bag 200 is more in line with the operation process implementation mode of the construction personnel. In some embodiments, the water injection on-off valve 400 can also be arranged on the side of the water injection part 220.

[0072] The sand layer geological pile foundation hole bottom grouting construction method according to the second aspect of the present application comprises the following steps:

[0073] Excavating the water storage tank and the sedimentation tank;

[0074] Measuring and laying out the pile foundation and burying the steel casing;

[0075] Drilling the stratum, and installing the sand layer geological pile foundation hole bottom grouting device according to any one of the first aspect of the present application into the drilled pile hole;

[0076] Pouring concrete into the pile foundation;

[0077] Grouting the hole bottom.

[0078] Specifically, referring to Figures 1 to 4, according to the requirements to arrange the site, to make construction preparation, excavation of sedimentation tank and reservoir, to make drainage system and ensure the recycling of water resources; pile foundation measurement and pile position lofting, steel casing is buried around the pile position; the stratum geology sand layer pile foundation hole bottom grouting device of the embodiment of the present application is placed in the pile hole after drilling construction of the stratum geology sand layer (before the device is placed, the water bag 200 can be first filled with water and placed in the steel reinforcement cage 100, or the water bag 200 can be filled with water and placed in the steel reinforcement cage 100 after the device is placed); then concrete pouring is carried out, and after the concrete solidification strength meets the design standard, the stratum geology sand layer pile foundation hole bottom grouting device is taken out to complete the hole bottom grouting.

[0079] According to the sand layer geology pile foundation hole bottom grouting construction method of the embodiment of the present application, the water storage tank and the sedimentation tank are excavated to form a drainage system, ensuring the recycling of water resources; the steel casing is buried to protect the hole pile, preventing hole collapse and avoiding affecting the construction progress and construction safety; the stratum geology sand layer pile foundation hole bottom grouting device of the embodiment of the present application is installed into the drilled pile hole to pour concrete on the pile foundation; when the pile foundation concrete reaches the design age, the water is discharged after the multiple water bags 200 are opened by the multiple water filling and opening valves 400, and the multiple channels are formed; finally, the multiple channels are grouted. Compared with the traditional grouting pipe construction method by pre-buried steel pipe, the water bag 200 is recycled in the embodiment of the present application, which saves steel and avoids quality problems caused by grouting pipe blockage, and also speeds up the construction progress.

[0080] In some embodiments of the present application, the stratum geology sand layer pile foundation hole bottom grouting device is obtained by the following steps:

[0081] The steel reinforcement cage 100 is made, which is composed of multiple main reinforcement bars 110 and multiple stirrups 120;

[0082] Multiple iron rings with an inner diameter of 30 mm are made, each iron ring is composed of multiple steel bars with an inner diameter of 6 mm, and the multiple iron rings are welded to the multiple main reinforcement bars 110 on the inner side of the steel reinforcement cage 100;

[0083] The water bag 200 is selected, which is a cylindrical body with a diameter of 20 mm and a polyurethane high molecular film structure;

[0084] The multiple water bags 200 are filled with water by using an external high-pressure water filling device and multiple water filling and opening valves 400, and the filling is stopped until the water storage part 210 of the multiple water bags 200 is full;

[0085] The multiple water bags 200 are coated with machine oil on the outer surface and placed in the multiple iron rings.

[0086] Specifically, in the process of making the steel cage 100, when the steel raw materials are delivered, a factory quality certificate or factory inspection report should be attached, and appearance inspection should be carried out. The unqualified steel bars are timely removed, and the marks on each bundle or each disc of the steel bars are checked whether the same as the model and batch number of the factory quality certificate, and whether the specifications and models meet the design requirements. According to the design drawing, a plurality of main reinforcement 110, stirrup 120 and reinforcing bar are welded into a steel cage 100 skeleton, the steel skeleton is assembled on site, the position is accurate and the welding is firm, the formed skeleton is stacked in the air, and after passing the quality inspection and supervision inspection, it can be used, and the hidden inspection record is carefully done. At the same time, when the external high-pressure water injection device is connected with the water injection switch valve 400, the water bag 200 needs to be injected according to the calculated pressure value meeting the standard. The outer surface of the plurality of water bags 200 is smeared with machine oil, so as to facilitate the demolding and taking out in the later period.

[0087] In some embodiments of the present application, the hole bottom is grouted, comprising the following steps:

[0088] The water in the plurality of water bags 200 is discharged through the plurality of water injection switch valves 400;

[0089] The plurality of water bags 200 are taken out from the sand layer geological pile foundation hole bottom grouting device;

[0090] After the plurality of water bags 200 are taken out, the plurality of holes formed by the pile foundation are cleaned;

[0091] The hole bottom of the plurality of holes is grouted.

[0092] Specifically, when the pile foundation concrete strength reaches the design value, the hole bottom grouting can be carried out. First, the water in the water bag 200 is discharged through the water injection switch valve 400 at the top of the water bag 200, the pressure in the water bag 200 is eliminated, and then the water bag 200 is pulled out. Then the pile head is chiseled to the design elevation, the hole left by the pile foundation after the water bag 200 is pulled out is cleaned with high-pressure water, and finally the hole bottom grouting is carried out through the hole. Among them, the two grouting pipes adopt circulating grouting when grouting, the grouting water-cement ratio is 0.6:1 to 0.8:1, the final hole pressure is 3.5 to 5 MPa, and the grouting amount is about 2.5 t.

[0093] In order to better facilitate the relevant technical personnel in the art to understand, one of the best embodiments of the present application is provided as follows:

[0094] (1) Excavate the reservoir and sedimentation tank:

[0095] According to the design requirements, the construction site is reasonably arranged, the site is first leveled, the sundries are removed, the soft soil is replaced, and the compaction is rammed. A drainage ditch is dug around the hole, and the drainage system is done well. When planning the driving route, keep a certain distance between the access road and the drilling position; so as not to affect the stability of the hole wall; the temporary spoil should be stacked 5m away from the hole, and the hole wall pressure should not be increased and transported to the spoil field in time.

[0096] The mud is transported by mud pump and mud discharge pipe. A pit is dug 2 meters away from the edge of the pile hole to serve as a sedimentation tank and a water storage tank, and the size thereof should meet the needs of pile sedimentation and mud replacement. The size of the sedimentation tank and the water storage tank is 4m (length) x 3m (width) x 3m (height), and the sedimentation tank and the water storage tank are separated by sandbags. After the mud is deposited, it flows into the water storage tank through the separation to ensure the recycling of water resources.

[0097] (2) Measure and lay out the pile foundation and bury the steel casing:

[0098] First, check and compare the coordinate base point, level base point and their measurement data provided by the design unit, and introduce them to the construction site. Then, use the total station to measure the center position of each bored pile according to the design, and the center of the drill bit or drill rod overlaps the center of the steel casing. 2-4 piles are set around the steel casing, reinforced with cement mortar, and obvious marks are set to measure the pile center position at any time. The pile position is laid out according to the "from the whole to the local principle", and the laid-out elevation should be rechecked in time when the elevation of the drill hole is laid out. The position of each pile point is accurately laid out by using the total station, so that the error is controlled within the specification requirements.

[0099] The buried steel casing is made of 8-10mm steel plate, and the inner diameter requirement is: according to the requirement, the buried steel casing with a diameter of 200mm larger than the design bored pile diameter is selected; the length of the casing is not less than 2000mm. The burial should be accurate and stable, and the deviation of the center from the pile center should not be greater than 5cm, and the inclination should not be greater than 1% of the pile depth, and the inclination of the buried part can be determined by the levelness of the horizontal plate.

[0100] (3) Drilling construction:

[0101] The drill is positioned, and the positioning process must be measured by the total station. The center of the drill bit is required to be aligned with the center of the steel casing, and the hole position should be rechecked in time during the drilling process to ensure that the hole center is consistent with the design center of the pile foundation. Otherwise, the reason should be found out and corrected in time.

[0102] During the drilling stage, some clay should be placed in the hole first, and an appropriate amount of stone with a particle size not greater than 15cm should be added, and the mud should be created by low stroke impact, and the specific gravity of the mud should be controlled within 1.1-1.3. When drilling to 0.5-1.5m, the clay should be backfilled again. Continue to impact with low stroke. Repeat two or three times, or more if necessary. If water loss is found during the impact process, the clay should be added immediately. If the mud is too thick and the drilling speed is slow, the cuttings should be removed and the mud should be replaced; the hole position should be checked in time during the drilling to ensure the correctness of the hole position until the drilling reaches the design stratum.

[0103] When the drilling depth reaches the design requirement, the hole depth, hole diameter, hole shape should be checked immediately with measuring rope and hole detector, and the hole is cleaned through water circulation of water inlet pipe and slurry discharge pipe. After the hole cleaning is completed, the thickness of the hole bottom sediment is checked, and the design requirements are confirmed. After the approval of the supervising engineer, the subsequent steel cage 100 installation can be prepared.

[0104] (4) The sand layer geological pile foundation hole bottom grouting device of the first aspect embodiment of the present application is manufactured:

[0105] Specifically, during the manufacturing of the steel cage 100, the steel bar raw material should be accompanied by a factory quality certificate or factory inspection report. The appearance inspection should be carried out, and the unqualified steel bars should be removed in time. The marks on each bundle or each disc of steel bars should be checked whether the same as the model and batch number of the factory quality certificate, and whether the specifications and models meet the design requirements.

[0106] According to the design drawing, a plurality of main reinforcement bars 110, stirrups 120 and reinforcing bars are welded into a steel cage 100 skeleton. The steel cage skeleton is assembled on site, the position is accurate and the welding is firm, the formed skeleton is stacked in the air, and it can be used only after passing the quality inspection and supervision inspection, and the hidden inspection record should be carefully done.

[0107] Start manufacturing the fixed guide mechanism 300, a plurality of iron rings with an inner diameter of 30 mm made of steel bars with an inner diameter of 6 mm are welded on the main reinforcement bars 110 of the steel cage 100, the distance between the iron rings is 2 m, the iron rings are not arranged on the bent part at the top end of the main reinforcement bars 110 of the steel cage 100, the iron ring located at the lowest position is 50 cm away from the bottom of the steel cage 100, and the steel cage 100 is installed with at least two groups of fixed guide mechanisms 300, i.e. at least two fixed guide units. Each fixed guide mechanism 300 in each fixed guide unit is symmetrically welded and installed on the inner side of the steel cage 100.

[0108] (5) Install the sand layer geological pile foundation hole bottom grouting device into the pile hole which has been drilled:

[0109] After the steel cage 100 skeleton is transported to the hole site, it is hoisted and placed in sections. The positions of the upper and lower main reinforcement bars 110 should be aligned to ensure that the upper and lower axes of the steel cage 100 are consistent. The lap joint positions of the main reinforcement bars 110 should be staggered by more than 50%. The adjacent two sections of the steel cage 100 skeleton are connected by welding. After the steel cage 100 is lowered into the hole, the total station instrument is used to check that the centerline deviation of the steel cage 100 is within the allowable range. Φ28 thick steel bars are used as positioning steel bars, which are welded and fixed to the casing in a "cross" shape along the outer edge of the steel cage 100 to position the steel cage 100. At the same time, it can prevent the steel cage from floating or deviating during concrete pouring.

[0110] (6) Water the water bag and install:

[0111] ​The water bag 200 adopts a cylindrical polyurethane high molecular film structure with a diameter of 20 mm, and can withstand an injection water pressure greater than the underwater concrete pouring pressure value. The water bag 200 is provided with an injection switch valve 400 at the top end, and an external high-pressure water injection device is connected to the injection switch valve 400 to inject water into the pressure-resistant water bag 200 according to the calculated pressure value. After the water injection is completed, the outer surface of the water bag 200 is smeared with machine oil to facilitate demolding in the later stage. Finally, the water bag 200 is worn in the fixing and guiding device.

[0112] (7) Concrete pouring for the pile foundation:

[0113] The concrete pouring is also called underwater concrete pouring. Before the underwater concrete pouring, the hole bottom sediment should be treated to meet the requirements. The concrete pouring should be arranged to measure the depth of the guide pipe and the height difference between the inside and outside of the guide pipe. The amount of the first batch of bottom sealing concrete should be sufficient to meet the requirement of the first buried depth of the guide pipe of more than 1.0 m. After the first batch of concrete is poured into the hole, the concrete should be continuously poured, and the buried depth of the guide pipe should be ensured to be 2.0-6.0 m. If the buried depth of the guide pipe exceeds 6 m, the guide pipe should be removed from the hole in reverse order. When the guide pipe is removed, the buried depth of the guide pipe should meet the above requirements, and the height difference between the concrete in the hole and the hole opening should be measured by a measuring rope before each time the guide pipe is removed. The length of the removed guide pipe is determined after calculation. The speed of the guide pipe removal should be controlled, and the guide pipe should not be pulled out of the concrete pouring surface. After the bottom sealing concrete is completed, the concrete pouring should be slowed down to prevent the steel reinforcement from floating up. The underwater concrete pouring should be higher than the design elevation by 0.5 m.

[0114] (8) Pile bottom grouting for the hole:

[0115] When the concrete strength of the pile foundation reaches the design value, the hole bottom grouting can be performed. First, the water in the water bag 200 is discharged through the water injection switch valve 400 at the top of the water bag 200 to eliminate the pressure in the water bag 200, and then the water bag 200 is pulled out. Then, the pile head is chiseled to the design elevation, the hole left by the pile foundation after the water bag 200 is pulled out is cleaned with high-pressure water, and finally the hole bottom grouting is performed through the hole. During the grouting, the two grouting pipes are used for cyclic grouting, the water-cement ratio of the grouting water is 0.6:1 to 0.8:1, the final hole pressure is 3.5 to 5 MPa, and the grouting amount is about 2.5 t.

[0116] In the description of the present specification, the description of the terms "one embodiment", "some embodiments", "exemplary embodiment", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the exemplary description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0117] While embodiments of the application have been shown and described, it is to be understood that the application is not limited to the details of the embodiments described, since the scope of the application will be defined with respect to the claims and their equivalents.

Claims

1. A sand layer geologic pile foundation hole bottom grouting device, characterized in that, The device comprises: a reinforcement cage; a plurality of water bags, each of which comprises a water storage part and a water injection part, the water storage part being arranged along the axial direction of the reinforcement cage, and the water injection part being located at the top of the water bag; a plurality of fixed guide mechanisms, each of which is arranged on the inner side of the reinforcement cage and connected with the main reinforcement of the reinforcement cage, and the plurality of fixed guide mechanisms are used together to define the positions of the plurality of water bags in the reinforcement cage; a plurality of water injection switch valves, each of which is connected with a water injection part; wherein, before the plurality of water bags are placed in the reinforcement cage, the surface of the water bag is smeared with machine oil; the plurality of fixed guide mechanisms are evenly grouped into a plurality of fixed guide units according to the number, and the plurality of fixed guide units are arranged on the inner side of the reinforcement cage in a vertical direction, each fixed guide mechanism in each fixed guide unit is located on the same horizontal plane and is arranged in a ring shape with equal spacing; the plurality of fixed guide mechanisms are a plurality of iron rings with an inner diameter of 30 mm, each of which is made of a steel reinforcement with an inner diameter of 6 mm, and the plurality of iron rings are welded with the plurality of main reinforcements; the plurality of water bags are a plurality of cylinders with a diameter of 20 mm; each of the water bags adopts a polyurethane high polymer film structure.

2. The sand stratum geological pile foundation hole bottom grouting device according to claim 1, characterized in that, The internal water injection pressure of each water bag is greater than the concrete pouring pressure.

3. The sand stratum geological pile foundation hole bottom grouting device according to claim 1, characterized in that, The plurality of water injection switch valves are respectively arranged at the top of the plurality of water injection parts.

4. A sand layer geologic pile foundation hole bottom grouting construction method, characterized in that, The device comprises the following steps: excavating a water storage pool and a sedimentation tank; measuring and laying out the pile foundation and burying a steel casing; drilling the stratum, installing the sand layer geological pile foundation hole bottom grouting device of any one of claims 1 to 3 into the drilled pile hole; pouring concrete into the pile foundation; grouting the hole bottom.

5. The sand stratum geological pile foundation hole bottom grouting construction method according to claim 4, characterized in that, The sand layer geological pile foundation hole bottom grouting device is obtained by the following steps: manufacturing a reinforcement cage, which is composed of a plurality of main reinforcements and a plurality of stirrups; manufacturing a plurality of iron rings with an inner diameter of 30 mm, each of which is composed of a plurality of steel reinforcements with an inner diameter of 6 mm, and the plurality of iron rings are welded on the plurality of main reinforcements on the inner side of the reinforcement cage; selecting water bags, which are cylinders with a diameter of 20 mm and a polyurethane high polymer film structure; using an external high-pressure water injection device and passing through a plurality of water injection switch valves to inject water into the plurality of water bags until the water storage part of the plurality of water bags is full, and then stopping the water injection; smearing machine oil on the outer surface of the plurality of water bags and placing them in the plurality of iron rings.

6. The sand layer geologic pile foundation hole bottom grouting construction method according to claim 5, characterized in that, The grouting of the hole bottom comprises the following steps: discharging the water in the plurality of water bags through the plurality of water injection switch valves; taking out the plurality of water bags from the sand layer geological pile foundation hole bottom grouting device; cleaning the plurality of channels formed by the pile foundation after taking out the plurality of water bags; grouting the hole bottom of the plurality of channels.

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