Cement-soil mixing pile construction system, methods, and cement-soil mixing piles

Abstract

This invention discloses a cement-soil mixing pile construction system, method, and cement-soil mixing pile. The upper end of the mixing paddle is hinged to the drill bit's clearance groove so that when the drill rod rotates downwards, the outward-swinging mixing paddle can mix and agitate the soil. When the drill rod drives the auger to rotate and drill down to a predetermined depth, and the connection between the auger and the drill rod is released, the drill rod is driven to rotate upwards at a predetermined speed, simultaneously injecting grout into the soil through the drill bit's outlet. At the same time, the mixing paddle, under the action of the auger, overcomes elastic force and swings into the clearance groove, thus rotating upwards relative to the auger until it leaves the soil. After the drill rod leaves the soil and grouting is completed, the heating element inside the auger heats up, heating the uncured cement-soil mixing pile and the surrounding soil, and reducing the moisture content of the mixing pile to a predetermined range. This allows for more thorough grout hydration during the pile formation process, thereby increasing the pile strength and improving the reinforcement effect on soft soil foundations.

Description

Technical Field

[0001] This invention relates to the field of cement mixing pile construction technology, and in particular to a cement-soil mixing pile construction system, method, and cement-soil mixing pile. Background Technology

[0002] my country has a vast territory with diverse soil types across different regions. Silty soft soil, mainly distributed in South China, is characterized by high compressibility, low bearing capacity, and high water content, posing a significant threat to the safety of surface buildings. Therefore, reinforcing the soft soil foundation is essential to improve the safety of buildings constructed on silty soft soil surfaces.

[0003] Cement mixing piles are a common method for reinforcing soft soil foundations. They use cement as a curing agent and employ specialized mixing machinery to forcibly mix the soft soil and curing agent deep within the foundation. The series of physicochemical reactions between the curing agent and the soft soil cause the soft soil to harden into a high-quality foundation with integrity, water stability, and a certain strength.

[0004] Currently, due to the complex underground soil conditions, factors such as inappropriate cement dosage and excessive water content in the soil during cement mixing pile construction have led to incomplete cement hydration and uneven cement-soil mixing during the pile formation process, which reduces the pile strength and the reinforcement effect on soft soil foundations. Summary of the Invention

[0005] The main objective of this invention is to propose a cement-soil mixing pile construction system, method, and cement-soil mixing pile, which aims to improve pile strength and the reinforcement effect of soft soil foundation.

[0006] To achieve the above objectives, the present invention proposes a cement-soil mixing pile construction system, comprising:

[0007] The drill rod has a drill bit at its lower end, and the drill bit has a clearance groove and a slurry outlet on its peripheral wall. The upper part of the drill rod has an installation position.

[0008] A mixing impeller, the upper end of which is hinged to a clearance groove and can swing around its hinge center relative to the inside and outside of the clearance groove. After swinging out of the clearance groove, the mixing impeller can be squeezed into the surrounding soil; and

[0009] An elastic element is provided in the clearance groove to apply an elastic force to the stirring paddle to drive it out of the clearance groove.

[0010] The mounting position is used to directly or indirectly detachably fix the upper end of the spiral tube. The lower end of the spiral tube extends downward along the drill rod to a position close to the stirring paddle. The spiral tube is used to remain in the borehole. An electric heating element is provided inside the spiral tube, which can generate heat when energized.

[0011] This invention also proposes a method for constructing cement-soil mixing piles, comprising the following steps:

[0012] S1. After laying out on the ground, the drill rod is driven to rotate by the drilling rig and drilled into the soil along with the auger until the target depth is reached.

[0013] S2. After disconnecting the spiral tube from the drill rod installation position, drive the drill rod to rotate upward at a predetermined speed, while simultaneously driving the slurry to be injected into the soil through the slurry outlet of the drill bit.

[0014] S3. After grouting is completed, the heating element inside the spiral pipe is energized to heat the uncured cement mixing pile and the surrounding soil, and to reduce the moisture content of the mixing pile.

[0015] S4. Stop heating after the moisture content of the cement mixing pile reaches the predetermined range, and the construction of the cement mixing pile is completed.

[0016] The present invention also proposes a cement-soil mixing pile, characterized in that it includes a pile body and a spiral tube surrounding the pile body, wherein the spiral tube is the aforementioned spiral tube.

[0017] The technical solution of this invention hinges the upper end of the mixing paddle to a clearance groove on the periphery of the drill bit, allowing the mixing paddle to swing around its hinge center relative to the clearance groove. An elastic element is provided in the clearance groove to apply a spring force to the mixing paddle, causing it to swing out of the clearance groove. This allows the mixing paddle to naturally swing out of the clearance groove under the elastic force of the elastic element. During the drilling process, the mixing paddle can further swing out of the clearance groove under the pressure of the soil below, increasing the amplitude of the mixing paddle squeezing into the soil. As the drill rod rotates and descends in the soil, it can mix the soil and create a flexing effect on the soil, thereby allowing the slurry to better diffuse along the surrounding soil and better bond with the soil. When the drill rod drives the auger to rotate and drill down to the predetermined depth, and the connection between the auger and the drill rod is released, the drill rod is driven to rotate upward at a predetermined speed, driving the grout (usually cement grout) into the soil through the grout outlet of the drill bit. At the same time, the mixing paddle, under the action of the auger and the soil, overcomes elastic force and swings into the clearance groove, thus rotating upward relative to the auger until it leaves the soil. After the drill rod leaves the soil and the grouting is completed, the heating element inside the auger can be energized to heat the uncured cement mixing pile and the surrounding soil, reducing the moisture content of the mixing pile to a predetermined range. This makes the hydration of the grout more thorough during the pile formation process. At the same time, the auger left in the soil wraps around the pile like tree roots, thereby increasing the pile strength and significantly improving the bearing capacity of the cement mixing pile, thus enhancing the reinforcement effect of soft soil foundations. Attached Figure Description

[0018] Figure 1 This is a three-dimensional schematic diagram of the drill rod and spiral tube assembled according to the present invention;

[0019] Figure 2 This is a cross-sectional view of the spiral tube of the present invention after the clearance groove has been formed;

[0020] Figure 3 This is a cross-sectional view of the spiral tube swing avoidance groove of the present invention;

[0021] Figure 4 This is a three-dimensional schematic diagram of the drill rod and spiral tube after disassembly according to the present invention;

[0022] Figure 5 This is a cross-sectional view of the cement mixing pile of the present invention;

[0023] Figure 6 Construction principle diagram of the present invention. Detailed Implementation

[0024] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0025] It should be noted that if the embodiments of the present invention involve directional indicators (such as up, down, left, right, front, back, top, bottom, inside, outside, vertical, horizontal, longitudinal, counterclockwise, clockwise, circumferential, radial, axial, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicators will also change accordingly.

[0026] Furthermore, if the embodiments of this invention involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, features defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. If the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0027] This invention proposes a cement-soil mixing pile construction system.

[0028] In embodiments of the present invention, such as Figures 1 to 6As shown, the cement-soil mixing pile construction system includes a drill rod 1, a mixing paddle 2, and an elastic element (not shown), all of which can be driven by a drilling rig 5. The lower end of the drill rod 1 has a drill bit 10, and the peripheral wall of the drill bit 10 is provided with a clearance groove 101 and a slurry outlet 11. The upper part of the drill rod 1 has an installation position 12. The upper end of the mixing paddle 2 is hinged in the clearance groove 101 and can swing inwards and outwards relative to the clearance groove 101 around its hinge center (generally referring to the center line of the hinge axis). After the mixing paddle 2 swings out of the clearance groove 101, it can be squeezed into the surrounding soil. The elastic element is provided in the clearance groove 101 to apply a spring force to the mixing paddle 2 to drive it out of the clearance groove 101, so that the mixing paddle 2 can naturally swing out of the clearance groove 101 under the action of the elastic force of the elastic element, and can further swing out of the clearance groove 101 under the pushing of the soil below during the rotation and drilling of the drill bit 10, increasing the amplitude of the mixing paddle 2 squeezing into the soil, so that when the drill rod 1 rotates down in the soil, it can stir the soil and form a turbulence on the surrounding soil, so that the slurry can better spread along the surrounding soil and better combine with the soil. Mounting position 12 is used to directly or indirectly detachably fix the upper end of the spiral tube 3. The lower end of the spiral tube 3 extends downward along the drill rod 1 to a position close to the mixing blade 2. When the drill rod 1 drives the spiral tube 3 to rotate and drill down to a predetermined depth and disconnects the spiral tube 3 from the mounting position 12 of the drill rod 1, the drill rod 1 is driven to rotate upward at a predetermined speed and the slurry (generally cement slurry) is driven to be injected into the soil through the slurry outlet 11 of the drill bit 10. At the same time, the mixing blade 2 overcomes the elastic force and swings into the avoidance groove 101 under the action of the spiral tube 3 and the soil, so that it can rotate upward relative to the spiral tube 3 until it leaves the soil. The spiral tube 3 is also equipped with an electric heating element (not shown). The electric heating element can generate heat when energized. When the drill rod 1 leaves the soil and grouting is completed, the electric heating element in the spiral tube 3 can be energized to heat the uncured cement mixing pile and the surrounding soil to accelerate the evaporation of water and reduce the moisture content of the mixing pile to a predetermined range. This makes the hydration of the grout more thorough during the cement mixing pile formation process. At the same time, the spiral tube 3 left in the soil wraps around the pile body 100 like the roots of a tree, thereby improving the pile strength and significantly increasing the bearing capacity of the cement mixing pile, thus improving the reinforcement effect of soft soil foundation.

[0029] In this embodiment of the invention, there are various ways in which the upper end of the spiral tube 3 can be detachably fixed to the mounting position 12. For example, it can be detachably fixed by means of a buckle structure, a clamp structure or a screw structure. In a preferred embodiment, the upper end of the spiral tube 3 is fixed with a ring 4 (such as by welding or screw structure). The ring 4 is sleeved on the drill rod 1 and is detachably fixed to the mounting position 12 of the drill rod 1 by a screw (not shown).

[0030] Specifically, in order to reduce the soil resistance experienced by the spiral tube 3 as it rotates downward with the drill rod 1, the lower end of the spiral tube 3 can be configured as a sharp cone shape.

[0031] The heating element is existing technology and can be, for example, a heating wire. It extends downwards along the spiral tube 3, with its upper end extending out of the spiral tube 3 to facilitate connection to an external power source. Since the heating element is existing technology, its specific structure and working principle will not be described in detail here.

[0032] In this embodiment of the invention, the moisture content of the uncured cement mixing pile can be obtained by various means, including but not limited to visual observation or detection by testing instruments. In a preferred embodiment, the invention further includes a time-domain reflectometry system (not shown), which includes a signal generator (not shown) and a signal processor (not shown). By measuring the relative permittivity of the soil around the borehole, the system can measure the moisture content of the soil around the borehole in real time, determine whether the moisture content of the soil after heating with a heating wire reaches a predetermined range, thereby improving the workability of the grout and enhancing the hydration effect, while also improving the heating effect of the heating element. Specifically, the time-domain reflectometry system is existing technology. It generally receives and reflects high-frequency electromagnetic wave signals emitted by the signal generator in the time-domain reflectometry system through a probe (not shown), calculates the time difference between the electromagnetic wave passing through the head and tail of the probe, and thus determines the relative permittivity of the soil.

[0033] In this embodiment of the invention, the number of stirring paddles 2 can be one or more, and the number of clearance grooves 101 corresponds to the number of stirring paddles 2. To make the drill bit 10 more evenly stressed, the number of stirring paddles 2 is preferably multiple (e.g., ...). Figure 1 (As shown in the case of two), multiple stirring paddles 2 are evenly distributed around the axis of drill bit 10.

[0034] Specifically, the agitator 2 is hinged to the clearance groove 101 via a hinge shaft 21. The elastic element can be a torsion spring (not shown) or a top spring (not shown). When it is a torsion spring, the torsion spring is sleeved in the hinge shaft 21, with one end of the torsion spring elastically abutting against the agitator 2 and the other end elastically opposite the drill bit 10, applying an outward swinging elastic force to the agitator 2. When it is a top spring, one axial end of the top spring is installed in the clearance groove 101, and the other axial end elastically abuts against the agitator 2, applying an outward swinging elastic force to the agitator 2.

[0035] Understandably, the number of slurry outlets 11 can be one or more. Having multiple outlets improves slurry discharge efficiency and ensures normal slurry discharge even if one outlet 11 is blocked. Specifically, the top surface of the drill rod 1 has a downwardly extending slurry channel 110, and the bottom of the slurry channel 110 extends to the slurry outlet 11, which penetrates the circumferential wall of the drill bit 10. Preferably, the multiple slurry outlets 11 are evenly distributed around the axis of the drill rod 1.

[0036] Furthermore, the upper wall of the clearance groove 101 is also provided with a limiting part 102. When the stirring paddle 2 swings outward to a predetermined angle, the stirring paddle 2 abuts against the limiting part 102 and can no longer swing outward, thereby limiting the swing amplitude of the stirring paddle. Specifically, the swing angle of the stirring paddle 2 can be determined as needed, preferably swinging outward to the maximum angle perpendicular to the axis of the drill rod 1.

[0037] It should be noted that the length and diameter ratio of the drill rod 1 can be determined according to the actual working conditions. The structure shown in the accompanying drawings is only for illustration and the length and diameter ratio of the drill rod cannot be limited by the drill rod structure shown in the drawings.

[0038] After introducing the implementation methods of the cement-soil mixing pile construction system of the present invention, the implementation methods of the method using the cement-soil mixing pile construction system of the present invention will be described next. The specific structure of the cement-soil mixing pile construction system is shown in the above embodiments, and repeated details will not be described again.

[0039] In embodiments of the present invention, such as Figures 1 to 6 As shown, the construction method for cement-soil mixing piles includes the following steps:

[0040] S1. After the ground is laid out, the drill rod 1 is rotated by the drill rig 5 and drilled into the soil along with the spiral pipe 3 until the target depth is reached.

[0041] Specifically, the layout before drilling is an existing technology, which aims to determine and mark the location of the cement mixing piles to be constructed. The specific operation process of the layout will not be described in detail here.

[0042] During the drilling process, the rotation speed and descent speed of drill rod 1 can be determined according to the actual working conditions. For example, the rotation speed is 22-28 r / min, preferably 25 r / min, and the descent speed can be 700-900 mm / min, preferably 800 mm / min.

[0043] Grouting can be performed simultaneously during drilling, or it can be done after drilling to the target depth.

[0044] Before drilling, the mixing paddle 2 can naturally swing out the clearance groove 101 under the elastic force of the elastic element. During the drilling process of the drill bit 10 rotating down, the clearance groove 101 can be further swinged out under the push of the soil below, increasing the amplitude of the mixing paddle 2 squeezing into the soil. When the drill rod 1 rotates down in the soil, it can stir the soil and flex the surrounding soil, so that the slurry can better spread along the surrounding soil and better combine with the soil.

[0045] S2. After disconnecting the spiral tube 3 from the installation position 12 of the drill rod 1, drive the drill rod 1 to rotate upward at a predetermined speed, while driving the slurry (generally referring to cement slurry) to be injected into the soil through the slurry outlet 11 of the drill bit 10.

[0046] Specifically, in step S2, the upward speed of drill rod 1 is 500-800 mm / min, preferably 500 mm / min, and the rotation speed is 22-28 r / min, preferably 25 r / min. This speed range can better ensure the grouting effect.

[0047] In step S2, grouting is stopped when the drill bit 10 rises to 0.5m above the ground to prevent grout from overflowing onto the ground, thereby ensuring the flatness of the construction site.

[0048] S3. After grouting is completed, the heating element inside the spiral pipe 3 is energized to heat the uncured cement mixing pile and the surrounding soil, and to reduce the moisture content of the mixing pile.

[0049] Step S3 also includes obtaining the moisture content of the uncured cement mixing pile by visual inspection or instruments. Specifically, the moisture content of the uncured cement mixing pile can be measured by using a time-domain reflectometry system to determine the relative permittivity of the soil surrounding the borehole. This allows for real-time measurement of the moisture content in the soil around the borehole, determining whether the moisture content of the soil after heating with a heating wire has reached a predetermined range. This improves the workability of the grout and enhances the hydration effect, while also improving the heating effect of the heating element. Understandably, the time-domain reflectometry system is existing technology. It typically uses a probe to receive and reflect high-frequency electromagnetic wave signals emitted by the signal generator in the time-domain reflectometry system, calculating the time difference between the electromagnetic wave passing through the probe head and tail to determine the relative permittivity of the soil.

[0050] S4. After the moisture content of the cement mixing pile reaches the predetermined range, heating is stopped, and the construction of the cement mixing pile is completed. This makes the slurry hydration more thorough during the cement mixing pile formation process. At the same time, the spiral pipe 3 left in the soil wraps around the pile body 100 like the roots of a tree, thereby improving the pile strength and significantly increasing the bearing capacity of the cement mixing pile, thus improving the reinforcement effect of soft soil foundation.

[0051] This invention also proposes a cement-soil mixing pile formed using the above-described cement-soil mixing pile construction method. In an embodiment of this invention, such as... Figure 5 As shown, the cement-soil mixing pile includes a pile body 100 and a spiral tube 3 surrounding the pile body 100. The structure of the spiral tube 3 is described in the above embodiment. In this invention, the slurry hydration during the cement-soil mixing pile formation process is more thorough. Simultaneously, the spiral tube 3 remaining in the soil wraps around the pile body 100 like tree roots, thereby increasing the pile strength and significantly improving the bearing capacity of the cement-soil mixing pile, thus enhancing the reinforcement effect of soft soil foundations.

[0052] The above description is merely a preferred embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformations made using the contents of the present invention's specification and drawings under the inventive concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A cement-soil mixing pile construction system, characterized in that, include: The drill rod has a drill bit at its lower end, and the drill bit has a clearance groove and a slurry outlet on its peripheral wall. The upper part of the drill rod has an installation position. A mixing impeller, the upper end of which is hinged to a clearance groove and can swing around its hinge center relative to the inside and outside of the clearance groove. After swinging out of the clearance groove, the mixing impeller can be squeezed into the surrounding soil; and An elastic element is provided in the clearance groove to apply an elastic force to the stirring paddle to drive it out of the clearance groove. The mounting position is used to directly or indirectly detachably fix the upper end of the spiral tube. The lower end of the spiral tube extends spirally downward along the drill rod to a position close to the stirring paddle. The spiral tube is used to be left in the borehole. An electric heating element is provided inside the spiral tube. The electric heating element can generate heat when energized. It also includes a time-domain reflectometry system, which is used to determine the relative permittivity of the soil around the borehole, thereby enabling real-time measurement of the water content in the soil around the borehole to determine whether the water content of the soil after heating with a heating wire has reached a predetermined range.

2. The cement-soil mixing pile construction system as described in claim 1, characterized in that: The lower end of the spiral tube is designed as a sharp cone shape.

3. The cement-soil mixing pile construction system as described in claim 1, characterized in that: The number of agitators is one or more, and the number of clearance slots corresponds to the number of agitators. When there are multiple agitators, they are evenly distributed around the axis of the drill bit.

4. The cement-soil mixing pile construction system as described in claim 1, characterized in that: The agitator is hinged to the clearance groove via a hinge shaft. The elastic element is a torsion spring or a top spring. When it is a torsion spring, the torsion spring is sleeved in the hinge shaft, with one end of the torsion spring elastically abutting against the agitator and the other end elastically opposite the drill bit. When it is a top spring, one axial end of the top spring is installed in the clearance groove, and the other axial end elastically abuts against the agitator.

5. The cement-soil mixing pile construction system as described in claim 1, characterized in that: The upper wall of the clearance groove is also provided with a limiting part. When the stirring paddle swings out to a predetermined angle, the stirring paddle abuts against the limiting part.

6. A construction method using the cement-soil mixing pile construction system as described in any one of claims 1 to 5, characterized in that, Includes the following steps: S1. After laying out on the ground, the drill rod is driven to rotate by the drilling rig and drilled into the soil along with the auger until the target depth is reached. S2. After disconnecting the spiral tube from the drill rod installation position, drive the drill rod to rotate upward at a predetermined speed, while simultaneously driving the slurry to be injected into the soil through the slurry outlet of the drill bit. S3. After grouting is completed, the heating element inside the spiral pipe is energized to heat the uncured cement mixing pile and the surrounding soil, and to reduce the moisture content of the mixing pile. S4. Stop heating after the moisture content of the cement mixing pile reaches the predetermined range, and the construction of the cement mixing pile is completed.

7. The construction method of the cement-soil mixing pile construction system as described in claim 6, characterized in that: Step S1 also includes the process of driving the grout into the soil through the grout outlet.

8. The construction method of the cement-soil mixing pile construction system as described in claim 6, characterized in that: Step S3 also includes using a time-domain reflectometry system to determine the relative permittivity of the soil around the borehole, thereby achieving real-time measurement of the water content in the soil around the borehole, in order to determine whether the water content of the soil after heating with a heating wire reaches a predetermined range.

Images