Method for constructing in-situ hardening piles using drilling machine

Abstract

A method for constructing a field-hardened pile using a drilling machine is disclosed. The method for constructing a field-hardened pile using a drilling machine according to an embodiment of the present invention comprises a ground drilling step of drilling the ground by a drilling machine to excavate to a target depth, an insertion step of inserting a tremie pipe and a vibratory compaction device into the drilled ground, a mortar manufacturing step of manufacturing mortar on-site, a mortar injection step of injecting the manufactured mortar into the drilled ground through a tremie pipe so as to form a pile body inside the drilled ground, and a withdrawal step of withdrawing the tremie pipe and the vibratory compaction device while operating the vibratory compaction device.

Description

Technology Field

[0001] The present invention relates to a method for constructing on-site hardened piles using a drilling machine, and more specifically, to a method for constructing on-site hardened piles using a drilling machine capable of forming a pile-shaped solidified body within the ground. Background Technology

[0002] If a building is constructed on weak soft ground, settlement or tilting of the structure may occur over time. To prevent these problems, pile foundations—a method of transferring loads by driving piles deep into the solid soil layer—are used.

[0003] Previously, PHC piles were mainly constructed using the driving or embedding methods.

[0004] However, the pile driving method generates vibration and noise due to impact during construction, and while the pile driving method is suitable for high-rise structures of 15 stories or more, it is uneconomical for mid-to-low-rise structures with relatively low loads due to excessive costs.

[0005] Methods for hardening the ground by injecting materials on-site instead of PHC piles include the chemical injection method, which involves injecting cement milk and chemicals after drilling; the cast-in-place aggregate pile method, which involves injecting cement paste after adding coarse aggregate of 20 mm or more into the excavated ground; the consolidation grouting method, which involves mixing stone powder and weathered granite soil on-site to fill with low-flow mortar; and the soil-cement method, which involves mixing cement paste with local soil to form a column body.

[0006] However, the chemical grouting method is not economically viable because it does not use aggregate, resulting in a high unit cement content of approximately 800 kg / m³ or more. The cast-in-place aggregate pile method involves a complex process and can lead to a prolonged construction period. The consolidation grouting method is difficult to control in terms of mixing quality and fluidity, as well as input quantity, due to the heterogeneous moisture content of the weathered granite soil and stone powder brought to the site. While the soil-cement method has the advantage of not requiring separate soil discharge due to its non-excavation nature, it has the disadvantage of a very low compressive strength of 2*.

[0007] Meanwhile, the expansive chemical pile method can achieve increased ground strength and suppression of settlement by consolidating the surrounding ground and lowering the moisture content through the expansion effect of quicklime, bentonite, aluminum powder, aluminum dross, etc.

[0008] However, piles made using quicklime exhibit a low strength of approximately 0.5 MPa, which can compromise work safety due to structural instability and rapid exothermic reactions. Additionally, bentonite is an imported mineral and has the disadvantage of rapidly decreasing swelling in the presence of salt. Aluminum powder poses a risk of dust dispersion because it requires fine particles, and its application in the field is difficult due to the need for specialized equipment. Aluminum dross is also difficult to use in the field because it generates severe heat and foul odors from harmful gases upon contact with water. Prior art literature

[0009] Korean Published Patent No. 10-2006-0044438 (Title of Invention: Composition of Consolidation-hardened Pile for Soft Ground Improvement, Published May 16, 2006) Korean Published Patent No. 10-1999-0048467 (Title of Invention: Auger Pile Construction Method Using Expandable Mortar, Published July 5, 1999) Korean Published Patent No. 10-2018-0052969 (Title of Invention: Expandable Mortar Composition for Civil Engineering Works, Published May 21, 2018) The problem to be solved

[0010] The objective of the present invention is to solve these conventional problems by providing a method for constructing on-site hardened piles using a drilling machine, which performs pre-drilling and injects mortar utilizing industrial by-products into the drilled ground to form a solidified body in the shape of a pile within the ground with constant strength and density.

[0011] The problems of the present invention are not limited to those mentioned above, and other problems not mentioned will be clearly understood by a person skilled in the art from the description below. means of solving the problem

[0012] To solve the above-mentioned problem, a field-hardened pile construction method using a drilling machine according to one aspect of the present invention may include a ground drilling step of drilling the ground with a drilling machine to excavate to a target depth, an insertion step of inserting a tremie pipe and a vibratory compaction device into the drilled ground, a mortar manufacturing step of manufacturing mortar at the site, a mortar injection step of injecting the manufactured mortar into the drilled ground through a tremie pipe so as to form a pile body inside the drilled ground, and a withdrawal step of withdrawing the tremie pipe and the vibratory compaction device while operating the vibratory compaction device.

[0013] In the mortar manufacturing stage, water-mixed expansive mortar is manufactured using a closed-type mortar mixer, and the expansive mortar is pumped and discharged into the ground through a tremie pipe using a hydraulic pump.

[0014] In the mortar manufacturing stage, an expansive mortar is manufactured using a field-hardened pile composition for soft ground improvement, wherein the field-hardened pile composition for soft ground improvement is characterized by being a mortar mixture comprising 15 to 1,000 parts by weight of blast furnace slag fine powder and 15 to 1,000 parts by weight of Type 1 cement, based on 100 parts by weight of process dust generated during a glass manufacturing process having a CaO content of 25 to 38 wt%, a Na2O content of 15 to 25 wt%, and a SO3 content of 35 to 50 wt%, and 20 to 3,000 parts by weight of circulating fluidized bed boiler bottom ash adjusted to a particle size of 0.01 to 10 mm as an aggregate.

[0015] The binder may further include 5 to 50 parts by weight of an expansive agent per 100 parts by weight of process dust, and the expansive agent may be characterized as being one or more mixtures selected from the group consisting of quicklime, calcined dolomite, quicklime dust collector dust and calcined dolomite dust collector dust.

[0016] The binder may further contain 5 to 200 parts by weight of fly ash having a CaO content of 15% or more per 100 parts by weight of process dust, and the fly ash may be characterized as being discharged from a fuel consisting of one or more mixtures selected from the group consisting of coal, solid fuel, organic sludge, and waste vinyl.

[0017] The ground drilling stage may be characterized by performing ground drilling using a non-excavation drilling method.

[0018] The vibratory compaction device includes a high-frequency vibrating rod, a power line supplying power to the vibrating rod, a flexible hose wrapping the power line, a winding drum winding the hose, and a drum motor that drives the winding drum to wind or unwind the hose. In the insertion stage, a tremie pipe is inserted into the drilled ground, and the drum motor is controlled so that the vibrating rod is positioned in the space between the bottom of the tremie pipe and the target depth, thereby unwinding the hose wound on the winding drum to lower the vibrating rod into the tremie pipe, and when the vibrating rod is positioned in the space, electricity can be supplied through the power line.

[0019] The vibratory compaction device includes a first sensor provided at the leading end of the vibrating rod and a second sensor provided in a hose connected to the vibrating rod, and may further include a process of decelerating the motor to reduce the descending speed of the vibrating rod when the first sensor detects a marker mounted on the bottom surface of the tremie tube, and stopping the motor and engaging the brake of the winding drum when the second sensor detects the marker.

[0020] It may further include a head trimming step for trimming the head formed by mortar, and a reinforcing mesh insertion step for inserting a reinforcing mesh assembled on the ground into the pile body before the pile body hardens. Effects of the invention

[0021] According to the field-hardened pile construction method using the drilling machine of the present invention, the following effects are achieved.

[0022] First, by performing pre-drilling and injecting mortar utilizing industrial by-products into the drilled ground, a pile-shaped solidified body can be formed within the ground with constant strength and density.

[0023] Second, it utilizes its own expansion force to consolidate the surrounding soft ground, and as a result, the shear strength and bearing capacity of the surrounding ground can be improved.

[0024] Third, it is constructed in a vertical direction and formed into a solidified body with a high compressive strength of 10 to 20 MPa, thereby simultaneously performing the role of a supporting pile to prevent settlement of the structure and a reinforcing pile to suppress lateral movement.

[0025] Fourth, by utilizing industrial by-products (circular resources) generated from glass manufacturing plants, power plants, steel mills, etc., for binders and aggregates, the extraction and damage of natural resources (cement and natural aggregates) can be reduced, and resource circulation and eco-friendliness can be secured.

[0026] The effects of the present invention are not limited to those mentioned above, and other unmentioned effects will be clearly understood by a person skilled in the art from the description in the claims. Brief explanation of the drawing

[0027] FIG. 1 shows a driving device for drilling according to one embodiment of the present invention. Figure 2 illustrates a drilling machine mounted on the leader of the drilling driving device of Figure 1. FIG. 3 shows a tremie pipe and a vibratory compaction device inserted into a drilled ground according to one embodiment of the present invention. Figure 4 shows the tremie tube illustrated in Figure 3 separately. Figure 5 shows the vibratory compaction device illustrated in Figure 3 separately. Figure 6 is an enlarged view of a part of the appearance in which the vibratory compaction device of Figure 5 is installed. FIG. 7 shows the internal configuration of a mortar manufacturing apparatus according to one embodiment of the present invention. FIG. 8 is a flowchart illustrating a method for constructing field-hardened piles using a drilling machine according to one embodiment of the present invention. Figure 9 shows a comparison between a field-hardened pile construction method using a drilling machine according to one embodiment of the present invention and a pile-shaped solidified body formed in the ground by a conventional pile construction method. Specific details for implementing the invention

[0028] The advantages and features of the present invention and the methods for achieving them will become clear by referring to the embodiments described below in detail together with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below but may be implemented in various different forms. These embodiments are provided merely to ensure that the disclosure of the present invention is complete and to fully inform those skilled in the art of the scope of the invention, and the present invention is defined only by the scope of the claims. Throughout the specification, the same reference numerals refer to the same components.

[0029] The size or shape of components depicted in the drawings attached to this specification may be exaggerated for clarity and convenience of explanation. It should be noted that identical components in each drawing may be depicted with the same reference numeral. Furthermore, detailed descriptions of functions and configurations of known technology that are deemed to unnecessarily obscure the essence of the invention may be omitted.

[0030] The terms used herein are for describing specific embodiments and are not intended to limit the invention. As used herein, the singular form may include the plural form unless the context clearly indicates otherwise. Furthermore, throughout this specification, when a part is described as "comprising" a certain component, it means that it may include additional components unless specifically stated otherwise.

[0031] When it is stated that one component is "connected" or "connected" to another component, it should be understood that while it may be directly connected or connected to that other component, there may also be other components in between. Conversely, when it is stated that one component is "directly connected" or "directly connected" to another component, it should be understood that there are no other components in between. Other expressions used to describe relationships between components should be interpreted in the same way.

[0032] Terms such as top, bottom, upper surface, lower surface, or upper, lower, used in this specification are used to distinguish relative positions among components. For example, while the upper part of a drawing may be designated as the upper part and the lower part as the lower part for convenience, in practice, the upper part may be designated as the lower part and the lower part as the upper part without departing from the scope of the present invention.

[0033] Terms including ordinal numbers, such as "the first," "the second," etc., as described in this specification may be used to describe various components, but said components are not limited by said terms. These terms are used merely to distinguish that each component is a different component and are not bound by the order of manufacture; furthermore, the names may not match between the detailed description of the invention and the claims.

[0034] All terms used herein, including technical or scientific terms, have the same meaning as generally understood by those skilled in the art to which the present invention pertains, unless otherwise defined. Terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant technology, and should not be interpreted in an ideal or overly formal sense unless explicitly defined in this specification.

[0035] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0036] FIG. 1 shows a driving device for drilling according to one embodiment of the present invention, and FIG. 2 illustrates a drilling machine mounted on the leader of the driving device for drilling of FIG. 1.

[0037] Referring to FIG. 1 and FIG. 2, a driving device (100) for drilling according to an embodiment of the present invention may be equipped with a main body (105), a driving part (110), a leader (120), a supporting joint part (130), a drilling machine (140), and a vibration compaction device (300).

[0038] The user (worker) can move the drilling driving device (100) to the work site through the operating means provided on the main body (105).

[0039] The driving unit (110) is composed of a crawler chassis, allowing for stable driving even on soft ground. That is, the driving unit (110) can be in the form of an endless track, thereby increasing the contact area with the ground and increasing the support capacity.

[0040] The leader (120) is a structure that guides the drilling machine (140) vertically (longitudinally) and maintains the verticality of the equipment during the process. The drilling machine (140) can be raised and lowered along the leader (120) which is erected in the longitudinal direction. To this end, a rail (122) may be installed in the longitudinal direction on the leader (120).

[0041] The support joint (130) supports the leader (120) and can be provided with a rotating and tilting structure to adjust the inclination, height, and direction of the leader (120). The support joint (130) can be provided with means such as a rotating shaft, a hydraulic cylinder, and a hinge plate, and can absorb reaction force and vibration during drilling operations to contribute to maintaining stable drilling precision even during non-excavation drilling.

[0042] The drilling machine (140) may be a device for forming a hole with a diameter of approximately 800 mm. The drilling machine (140) may be driven, for example, by hydraulic power to drill the ground. The drilling machine (140) may perform ground drilling to a target depth in a non-excavation manner.

[0043] The drilling machine (140) is for drilling and excavating the ground vertically and may include a coupling part (150) that sequentially engages with a rotary motor as it moves downward in the longitudinal direction, a side convex part (160) that protrudes convexly in the transverse direction to prevent the upward movement of excavated soil during the excavation of the ground and induces the soil to flow in the transverse direction so that the borehole wall is pressed in the transverse direction and the consolidation of the soft ground proceeds, and a rod part (170) that is integrally provided with a screw blade (175) wound in a spiral shape on its outer surface.

[0044] The side convex portion (160) may have a configuration in which a first section (162) that is sequentially tapered downward as it goes downward in the longitudinal direction, a cylindrical second section (164), and a third section (166) that is tapered downward are in succession.

[0045] The first section (162) consists of a downwardly expanding tapered section in which the longitudinal circular cross-sectional size gradually increases as it moves downward in the longitudinal direction. The second section (164) following the first section (162) consists of a cylindrical section in which the longitudinal circular cross-sectional size is constant. The third section (166) following the second section (164) consists of a downwardly contracting tapered section in which the longitudinal circular cross-sectional size gradually decreases as it moves downward in the longitudinal direction. Also, the longitudinal length of the first section (162) may be shorter than the longitudinal length of the third section (166).

[0046] Since a side convex portion (160) with a larger longitudinal circular cross-sectional size than the rod portion (170) is formed longitudinally upward of the rod portion (170), while the rod portion (170) rotates and excavates the ground by the screw blade (175), the soil pushed toward the side convex portion (160) is no longer discharged upward due to the convex shape of the side convex portion (160) and is pushed toward the lateral borehole wall, thereby pressing the borehole wall laterally, and consequently, consolidation is achieved with respect to the borehole wall laterally.

[0047] The side convex portion (160) itself prevents the collapse of the borehole wall, and the upward movement of the excavated soil is blocked by the side convex portion (160), and instead the soil is pushed laterally, applying pressure to the borehole wall, causing lateral ground consolidation to occur.

[0048] Although not illustrated, a pressure gauge capable of measuring pressure may be provided on the side convex portion (160). The pressure gauge may be installed along the longitudinal boundary line between the first section (162) and the second section (164) or between the second section (164) and the third section (166). The pressure generated as soil is pushed toward the borehole wall during the excavation process can be measured in real time by the pressure gauge. Through this, the operator can verify the ground reinforcement effect caused by consolidation during the drilling process in real time. Furthermore, by easily obtaining a physical quantity that serves as an indicator for evaluating the bearing capacity of the non-excavated pile, the pressure to be applied to the pile can be reliably predicted and utilized for quality control of pile design and pile construction.

[0049] The above-described drilling machine (140) is not limited to that type, and various conventional known drilling machines of different structures and shapes may be used.

[0050] The vibratory compaction device (300) can be mounted on one side of the leader (120) of the drilling driving device (100) and is used to remove air bubbles contained in the mortar. This will be explained in detail in FIG. 5.

[0051] Although not illustrated, the drilling driving device (100) may include means such as a reduction gear (gearbox) for controlling the rotational force and torque of the auger drill, a control torque meter for measuring the torque generated during auger rotation in real time, a vertical sensing sensor for detecting the verticality of the leader or auger for accurate vertical drilling, and a toe cell for measuring the ground contact force and pressure of the auger.

[0052] FIG. 3 shows a tremie pipe and a vibratory compaction device inserted into a drilled ground according to one embodiment of the present invention, and FIG. 4 separately shows the tremie pipe illustrated in FIG. 3.

[0053] Referring to FIG. 3, a tremie pipe (200) and a vibratory compaction device (300) are inserted into the ground drilled by a drilling machine (140) mounted on a drilling driving device (100).

[0054] At this time, the tremie pipe (200) may be inserted into the drilled ground first, and then the vibratory compaction device (300) may be inserted into the tremie pipe (200), or the tremie pipe (200) and the vibratory compaction device (300) may be inserted simultaneously while the vibratory compaction device (300) is inserted into the tremie pipe (200). In the embodiment of the present invention, the former is explained as an example.

[0055] The tremie pipe (200) can be inserted into the drilled ground for a length of approximately up to 16 m to allow mortar to fill from the bottom of the drilled ground. The diameter of the tremie pipe (200) can be approximately 220 mm to 260 mm.

[0056] The tremie pipe (200) may be composed of, for example, a steel pipe or a PVC pipe, and the lower part (bottom) is positioned at a certain distance from the bottom of the bore hole so that the mortar injected into the bore hole through the tremie pipe (200) is uniformly and effectively discharged.

[0057] Referring to FIG. 4, the tremie tube (200) may be provided in the shape of a cylindrical rod and may include a hopper (210), a transfer tube (220), and a connecting part (230).

[0058] The tremie tube (200) can be provided in a modular manner in which several transfer tubes (220) are combined by a connecting part (230).

[0059] The hopper (210) is an inlet part into which mortar is injected, and the mortar injected into the hopper (210) flows into the tremie pipe (200) by gravity.

[0060] The hopper (210) may be provided in a funnel shape. The hopper (210) may be maintained with at least one portion protruding outward from the top of the drilled ground, and for this purpose, the lower portion may be supported by a base (212, see FIG. 3). The base (212) may be provided in a flat plate shape having a diameter larger than the drilled hole (H1) in the ground and may be placed in the drilled area before the tremie tube (200) is inserted into the drilled ground. An insertion hole (not shown) is formed in the central portion of the base (212), and the tremie tube (200) may be inserted into the drilled ground through the insertion hole of the base (212).

[0061] In another embodiment, wires (not shown) are connected to both sides of the hopper (210) and the wires are secured to a part of the drilling driving device (100) described above so that the tremie tube (200) inserted into the drilled ground can be maintained at a certain height, in which case the support (212) can be omitted.

[0062] The transfer pipe (220) is a part where mortar fed from the hopper (210) moves downward by gravity. The transfer pipe (220) has a constant diameter and wear resistance, and its inner surface is smooth so that the material (e.g., mortar) flows without blockage.

[0063] A connecting portion (230) is provided at each end of the transfer pipe (220) so that the hopper (210) and the transfer pipe (220) or the transfer pipes (220) can be connected to each other. Through this, the length of the tremie pipe (200) can be adjusted according to the depth of the ground drilled.

[0064] A thread is formed in the connecting part (230) so that a screw connection can be made by rotating the hopper (210) and the transfer pipe (220) or the transfer pipes (220) to interlock with each other. In other embodiments, the connecting part (230) may be manufactured in a screw-type, flange-type, or clamp-type structure. Through this, the length of the tremie pipe (200) can be extended by connecting multiple transfer pipes (220) to match the construction depth, or the length of the tremie pipe (200) can be reduced by separating some of the transfer pipes (220).

[0065] Figure 5 shows the vibratory compaction device illustrated in Figure 3 separately, and Figure 6 shows an enlarged view of a part of the installed vibratory compaction device of Figure 5.

[0066] The vibration compaction device (300) according to an embodiment of the present invention can improve the density of the pile body by providing vibration energy that increases the fluidity and filling properties of the mortar.

[0067] Referring to FIG. 5(a) and FIG. 6, the vibratory compaction device (300) may include a vibrating rod (310), a power line (not shown) that supplies power to the vibrating rod (310), a flexible hose (320) that wraps the power line, a winding drum (330) that winds the hose (320), a drum motor (340, see FIG. 1) that drives the winding drum (330) to wind or unwind the hose, a first sensor (351), a second sensor (352), and a processor (360).

[0068] The vibrating rod (310) can be provided in a cylindrical shape of a certain length, for example. The vibrating rod (310) can remove air bubbles in the mortar injected into the ground drilled through the tremie tube (200) by vibration, and this vibration temporarily reduces the frictional resistance between particles in the mortar, thereby improving fluidity and filling properties, and is effective in increasing the strength of the pile body after hardening.

[0069] The vibratory compaction device (300) can generate vibrations using a high-frequency power source. As illustrated in FIG. 5(b), a rotating body (312) with an eccentric mass (312a) formed on one side may be provided inside the vibrating rod (310). A key (314a) protruding from the head of the vibrating motor (314) may be coupled to the keyway (312b) of the rotating body (312). When power is supplied, the vibrating motor (314) rotates at high speed, causing the eccentric mass (312a) of the rotating body (312) to generate an unbalanced centrifugal force. This centrifugal force is transmitted to the outer wall of the vibrating rod (310) to vibrate the surrounding mortar. The internal configuration of the vibrating rod (310) described above can be modified into various conventional known vibration structures.

[0070] High-frequency vibrations generated by the vibratory compaction device (300) remove air bubbles in the mortar and rearrange particles to improve filling properties and density. In particular, the high-frequency vibration rod (310) has a higher vibration frequency than a general vibrator, so it can quickly transmit finer vibrations and is effective in forming a homogeneous solidified body (pile body) in a short time.

[0071] The hose (320) is flexibly provided and wound onto a winding drum (330) to protect the outer sheath of the power line.

[0072] The winding drum (330) can be positioned on one side of the leader (120) of the drilling driving device (100) (see FIG. 1), and can be rotated by a drum motor (340) to wind or unwind the hose (320) and raise or lower the vibrating rod (310) inside the tremie tube (200).

[0073] The first sensor (351) is provided at the leading end of the vibrating rod (310), and the second sensor (352) can be provided in a hose (320) connected to the vibrating rod (310) at a certain distance from the first sensor (351).

[0074] At this time, a marker (202) may be provided on the bottom surface of the tremie tube (200). The marker (202) may be attached to the bottom surface of the inner or outer side of the tremie tube (200) and may be provided in the form of, for example, a magnetic marker, a metal ring, etc.

[0075] The first sensor (351) and the second sensor (352) may include a magnetic field sensing sensor, a metal sensing sensor, etc., for detecting the marker (202).

[0076] After the tremie tube (200) is inserted into the drilled ground, the processor (360) controls the drum motor (340) so that the vibrating rod (310) is positioned in the space between the bottom surface of the tremie tube (200) and the target depth, thereby unwinding the hose (320) wound on the winding drum (330) to lower the vibrating rod (310) into the tremie tube (200), and when the vibrating rod (310) is positioned in the space between the bottom surface of the tremie tube (200) and the target depth, electricity can be supplied through a power line by a power supply unit (not shown).

[0077] When the first sensor (351) detects the marker (202), the processor (360) can reduce the driving speed of the drum motor (340) to reduce the downward speed of the vibrating rod (310), and when the second sensor (352) detects the marker (202), it can stop the drum motor (340) and engage the brake of the winding drum (330). Afterwards, the vibration compaction device (300) can supply power to generate vibration in the vibrating rod (310).

[0078] Conventionally, the method involved the user holding a hose and moving the vibrating rod to the required position to perform the work. However, in an embodiment of the present invention, a vibrating compaction device (300) is mounted on a driving device (100) for drilling, and the winding drum (330) is rotated by a drum motor (340) to lower the vibrating rod (310) to the lowest point in the drilled ground, thereby increasing work convenience.

[0079] In other words, instead of the user manually lowering the vibrating rod and checking its position, automatic depth control is possible to automatically position the vibrating rod in a space near the target depth, thereby improving work efficiency.

[0080] FIG. 7 shows the internal configuration of a mortar manufacturing apparatus according to one embodiment of the present invention.

[0081] In order to inject mortar into the aforementioned tremie pipe (200), mortar can be manufactured on-site.

[0082] Referring to FIG. 7, a mortar manufacturing device (400) according to an embodiment of the present invention may include a closed-type mortar mixer (410), a mixer drive motor (420), an air pressure generator (430), a storage tank (440), and a hydraulic pump (450). The mortar produced by the mortar manufacturing device (400) may be fed (discharged) into a tremie pipe (200) through a transfer hose (not shown) connected to the mortar manufacturing device (400).

[0083] The closed-type mortar mixer (410) can produce expansive mortar mixed with water. Since the closed-type mortar mixer (410) has a closed structure, internal pressure control is possible, and moisture evaporation or the mixing of external foreign matter can be prevented. In addition, it is possible to produce low W / B (water / binder ratio) mortar and ensure quality. Unlike the conventional open-type method, the mixer (410) is provided in a closed type, so there is almost no moisture loss and the separation of the mortar can be prevented.

[0084] The mixer drive motor (420) rotates the stirring blades of the mixer (410) and controls the mixing speed and rotational torque using an electric or hydraulic drive method so that the mortar material can be mixed uniformly.

[0085] The air pressure generator (430) can be used to generate pressure within the transfer line using air pressure when discharging the manufactured mortar, or for pneumatic control such as operating valves or driving cylinders. The air pressure generator (430) can also generate air pressure to regulate the pressure in the mixer (410) or the storage tank (440). The air pressure can also be used for mortar transfer or valve operation.

[0086] The storage tank (440) is a tank for temporarily storing mortar, and the mortar completed in the mixer (410) can be transferred to the storage tank (440) by means such as internal pressure, gravity, or a pump. The storage tank (440) can be provided in a sealed form, thereby blocking contact with the outside air to prevent material separation or moisture evaporation.

[0087] The hydraulic pump (450) pumps and discharges expansive mortar into the hopper (210) of the tremie pipe (200) inserted into the drilled ground.

[0088] The mortar manufacturing device (400) can manufacture expansive mortar using a field-hardened pile composition for improving soft ground.

[0089] The composition of the field-hardened pile for improving soft ground may be a mortar mixture comprising 20 to 3,000 parts by weight of circulating fluidized bed boiler bottom ash adjusted to a particle size of 0.01 to 10 mm as an aggregate, to a binder comprising 15 to 1,000 parts by weight of blast furnace slag fine powder and 15 to 1,000 parts by weight of Type 1 cement, based on 100 parts by weight of process dust generated during a glass manufacturing process having a CaO content of 25 to 38 wt%, a Na2O content of 15 to 25 wt%, and a SO3 content of 35 to 50 wt%.

[0090] The aforementioned Type 1 cement may be a general product available on the market to enhance early strength. It is preferable to include 15 to 1,000 parts by weight of Type 1 cement per 100 parts by weight of process dust. If the content of Type 1 cement is less than 15 parts by weight, early strength cannot be achieved, and if it is incorporated in excess of 1,000 parts by weight, it is not economically viable and may not be environmentally friendly as hexavalent chromium, etc., may leach out.

[0091] The aforementioned circulating fluidized bed boiler bottom ash is discharged from power plants that use as fuel one or more mixtures selected from the group consisting of coal, general solid refuse fuel (SRF), biomass-solid refuse fuel (BIO-SRF), and organic sludge. Circulating fluidized bed boiler bottom ash has a relatively low SiO2 content and a large amount of CaO content, so it has self-expanding properties when reacting with water.

[0092] Circulating fluidized bed boiler bottom ash can exist in the form of large lumps due to the mutual fusion of some materials with lowered melting points, but if the particle size is adjusted to 0.01 to 10 mm, it can function as an aggregate that can replace weathered granite soil or stone powder used in conventional consolidation grouting methods.

[0093] It is preferable that the circulating fluidized bed boiler bottom ash be included in an amount of 20 to 3,000 parts by weight per 100 parts by weight of process dust. If the circulating fluidized bed boiler bottom ash is less than 20 parts by weight, the amount of binder increases relatively, leading to excessive viscosity and unfavorable economic efficiency. Conversely, if it exceeds 3,000 parts by weight, the amount of aggregate increases relatively, making it impossible to develop strength, and the lack of viscosity may cause material separation.

[0094] In addition, the binder further includes 5 to 50 parts by weight of an expansive agent per 100 parts by weight of process dust, and the expansive agent may be one or more mixtures selected from the group consisting of quicklime, calcined dolomite, quicklime dust collector dust, and calcined dolomite dust collector dust. Quicklime and calcined dolomite may be used as general products available on the market, and quicklime dust collector dust and calcined dolomite dust collector dust may be used as process by-products collected in the kiln bag filter during the calcination process of limestone and dolomite.

[0095] For every 100 parts by weight of the aforementioned process dust, it is preferable to mix 5 to 50 parts by weight of the expansion agent. If the amount is less than 5 parts by weight, the effect is not exerted, and if the amount exceeds 50 parts by weight, it expands excessively, which can cause cracking of the mortar and significantly reduce its strength.

[0096] In addition, in another example, the binder further includes 5 to 200 parts by weight of fly ash having a CaO content of 15% or more per 100 parts by weight of process dust, and the fly ash may be discharged from a fuel consisting of one or more mixtures selected from the group consisting of coal, general solid refuse fuel (SRF), biomass-solid refuse fuel (BIO-SRF), and waste vinyl.

[0097] The aforementioned fly ash can suppress material separation by adsorbing excess water present in the mortar and increasing viscosity. Additionally, the incorporation of fly ash in the form of fine powder has the advantage of reducing pipe wear through friction with circulating fluidized bed boiler bottom ash during the mortar's transport through pipes. Furthermore, the fly ash can cause expansion upon contact with water, thereby enhancing the strength of the surrounding ground through consolidation.

[0098] In an embodiment of the present invention, by constructing a pile (body) using expansive mortar, the surrounding soft ground is consolidated using its own expansive force, and as a result, the shear strength and bearing capacity of the surrounding ground can be improved.

[0099] In addition, it is constructed in a vertical direction and formed into a solidified body with a high compressive strength of 10 to 20 MPa, thereby simultaneously performing the role of a supporting pile to prevent settlement of the structure and a reinforcing pile to suppress lateral movement.

[0100] In addition, by utilizing industrial by-products (circular resources) generated from glass manufacturing plants, power plants, steel mills, etc., for binders and aggregates, the extraction and damage of natural resources (cement and natural aggregates) can be reduced, and resource circularity and eco-friendliness can be ensured.

[0101] FIG. 8 is a flowchart illustrating a method for constructing field-hardened piles using a drilling machine according to one embodiment of the present invention.

[0102] Referring to FIG. 8, the field hardening pile construction method using a drilling machine according to an embodiment of the present invention first drills the ground to a target depth using a drilling machine (140) provided in a drilling driving device (100) (S701).

[0103] At this time, ground drilling can be carried out using a non-excavation drilling method.

[0104] Next, an insertion step is performed to insert the tremie pipe (200) and the vibratory compaction device (300) into the drilled ground (S711).

[0105] In the insertion step (S711), the tremie pipe (200) is first inserted into the drilled ground, and then the vibratory compaction device (300) can be inserted into the tremie pipe (200). Since the specific method of installing or inserting the tremie pipe (200) and the vibratory compaction device (300) has been described in detail in FIGS. 3 to 6, a detailed explanation is omitted.

[0106] Next, a mortar manufacturing step is performed to manufacture mortar on-site (S721).

[0107] In the mortar manufacturing step (S721), the mortar manufacturing device (400) can manufacture an expansive mortar using a field-hardened pile composition for soft ground improvement as described above. At this time, water may be mixed into the expansive mortar.

[0108] Next, a mortar injection step is performed in which mortar manufactured to form a pile body inside the drilled ground is injected into the drilled ground through a tremie pipe (200) (S731).

[0109] In the mortar injection step (S731), the mortar injected through the tremie pipe (200) is discharged through the bottom of the tremie pipe (200) to fill the inside of the drilled ground. By injecting the mortar from the bottom to the top through the tremie pipe (200), air trapping or separation phenomena can be prevented. When the mortar is mixed with surrounding soil, a pile body integrated with the ground can be formed.

[0110] Next, a pulling step is performed to pull out the tremie pipe (200) and the vibratory compaction device (300) while operating the vibratory compaction device (300) (S741).

[0111] In the extraction step (S741), air bubbles in the mortar can be effectively removed by the vibration of the vibratory compaction device (300). Here, while extracting the tremie pipe (200) and the vibratory compaction device (300), mortar can be injected into the drilled ground through the tremie pipe (200) simultaneously.

[0112] After sufficient mortar has been injected, during the process of pulling it out together with the tremie pipe (200) while operating the vibratory compaction device (300), the vibration can improve the density of the mortar and remove air bubbles, thereby increasing the integrity of the pile body.

[0113] Next, a head trimming step is performed to trim the head formed by the mortar (S751).

[0114] Subsequently, a reinforcing mesh insertion step may be performed in which the reinforcing mesh assembled on the ground is inserted into the pile body before the pile body hardens.

[0115] The symbols attached to each of the aforementioned steps are used to identify each step and do not indicate the order of the steps among themselves; the steps may be performed differently from the specified order unless a specific order is clearly indicated in the context.

[0116] Figure 9 shows a comparison between a field-hardened pile construction method using a drilling machine according to one embodiment of the present invention and a pile-shaped solidified body formed in the ground by a conventional pile construction method.

[0117] Referring to FIG. 9(a), according to the field-hardened pile construction method using a drilling machine according to an embodiment of the present invention, pre-drilling is performed and an expansive mortar utilizing industrial by-products is injected into the drilled ground to form a solidified body in the form of a vertical pile within the ground with constant strength or density.

[0118] On the other hand, referring to Fig. 9(b), in the case of pile construction using the conventional high-pressure injection method (JSP) or low-flow mortar injection method (CGS), the improvement material may not sufficiently penetrate or bond to the hard strata. Additionally, near the lower rock layer, there is a possibility that the injection material will not be consolidated or will backflow. Consequently, discontinuities and non-uniform shapes may occur between the improvement materials.

[0119]

[0120] Table 1 above shows the test results after performing test construction according to the field-hardened pile construction method using a drilling machine according to an embodiment of the present invention.

[0121] After test construction, verification boring was performed at 7 and 28 curing days, and compressive strength was measured for each curing day up to 56 days. That is, after a certain period (7 and 28 days) had passed since construction, the modified specimen was bored (sampled) to check the hardening state, and the compressive strength according to different curing days (age) was compared to analyze the trend of strength increase over time. Here, the sample taken at 7 curing days was measured to have a lower compressive strength than the sample taken at 28 final curing days.

[0122] Furthermore, it was confirmed that samples taken from the lower part exhibited greater compressive strength than those from the upper part. In the lower part, the material has a higher unit weight and less moisture loss, allowing hydration to proceed more stably and resulting in relatively higher strength.

[0123] When comparing the compressive strength after 56 days of curing, it was confirmed that the average compressive strength of the sample taken 28 days after construction was similar to the strength of the sample prepared on-site. In other words, it can be seen that the quality of on-site construction is good and the design target strength was appropriately achieved.

[0124] As described above, preferred embodiments of the present invention have been illustrated and described with reference to the drawings; however, the present invention is not limited to the specific embodiments described above. Various modifications are possible by those skilled in the art without departing from the essence of the invention as claimed in the patent claims, and such modifications should not be understood individually from the technical spirit or perspective of the present invention. Explanation of the symbols

[0125] 100: Drilling driving device 105: Main body 110: Driving Unit 120: Leader 130: Support joint 140: Drill 150: Joint 160: Side convex part 170: Rod Section 200: Tremie Section 202: Marker 210: Hopper 212: Base 220: Transfer pipe 230: Connection part 300: Vibratory compaction device 310: Vibration rod 320: Hose 330: Winding drum 340: Motor 351: 1st sensor 352: 2nd sensor 360: Processor 400: Mortar manufacturing device 410: Closed-type mortar mixer 420: Mixer drive motor 430: Air pressure generator 440: Storage tank 450: Hydraulic pump

Claims

Claim 1 A method for constructing a field-hardened pile using a drilling machine, comprising: a ground drilling step of drilling the ground by a drilling machine to excavate to a target depth; an insertion step of inserting a tremie pipe and a vibratory compaction device into the drilled ground; a mortar manufacturing step of manufacturing mortar at the site; a mortar injection step of injecting the manufactured mortar into the drilled ground through the tremie pipe so as to form a pile body inside the drilled ground; and a withdrawal step of withdrawing the tremie pipe and the vibratory compaction device while operating the vibratory compaction device; wherein the vibratory compaction device comprises a vibratory rod, a hose connected to the vibratory rod, a winding drum winding the hose, a drum motor that drives the winding drum to wind or unwind the hose, and a sensor provided on the vibratory rod, and wherein the position of the vibratory rod inserted into the tremie pipe is detected through the sensor and the drum motor is controlled to adjust the lifting speed of the vibratory rod or the position of the vibratory rod. Claim 2 A method for constructing on-site hardened piles using a drilling machine, wherein, in claim 1, the ground drilling step is characterized by performing ground drilling using a non-excavation drilling method. Claim 3 A method for constructing on-site hardened piles using a drilling machine, characterized in that, in the mortar manufacturing step, an expansive mortar is manufactured by a closed-type mortar mixer, and in the mortar injection step, a hydraulic pump is used to pump and discharge the expansive mortar into the drilled ground through the tremie pipe. Claim 4 A method for constructing a field-hardened pile using a drilling machine according to claim 3, wherein the field-hardened pile composition for soft ground improvement is used to manufacture the expansive mortar in the mortar manufacturing step, and wherein the field-hardened pile composition for soft ground improvement is a mortar mixture comprising 15 to 1,000 parts by weight of blast furnace slag fine powder and 15 to 1,000 parts by weight of Type 1 cement, based on 100 parts by weight of process dust generated during a glass manufacturing process having a CaO content of 25 to 38 wt%, a Na2O content of 15 to 25 wt%, and an SO3 content of 35 to 50 wt%, and 20 to 3,000 parts by weight of circulating fluidized bed boiler bottom ash adjusted to a particle size of 0.01 to 10 mm as an aggregate. Claim 5 A method for constructing on-site hardened piles using a drilling machine according to claim 4, wherein the binder further comprises 5 to 50 parts by weight of an expansive agent per 100 parts by weight of the process dust, and the expansive agent is one or more mixtures selected from the group consisting of quicklime, calcined dolomite, quicklime dust collection dust, and calcined dolomite dust collection dust. Claim 6 A method for constructing on-site hardened piles using a drilling machine according to claim 4, wherein the binder further comprises 5 to 200 parts by weight of fly ash having a CaO content of 15% or more per 100 parts by weight of the process dust, and wherein the fly ash is discharged from a fuel composed of one or more mixtures selected from the group consisting of coal, solid fuel, organic sludge, and waste vinyl. Claim 7 A method for constructing an on-site hardened pile using a drilling machine according to claim 1, wherein the drum motor is controlled so that the vibrating rod is positioned in the space between the bottom surface of the tremie pipe and the target depth, thereby unwinding the hose wound on the winding drum to lower the vibrating rod into the tremie pipe, and when the vibrating rod is positioned in the space, electricity is supplied through a power line. Claim 8 A method for constructing a field-hardened pile using a drilling machine according to claim 1, further comprising a head trimming step for trimming the head formed by the mortar and a reinforcing mesh insertion step for inserting a reinforcing mesh assembled on the ground into the pile body before the pile body hardens.

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