Method for forming micro steel pipe pile with reinforced core and solid waste combined grouting

Abstract

The present application provides a kind of micro steel pipe pile stiff core and solid waste combined strengthening grouting pipe pile forming method, comprising the following steps: pipe pile grouting pile, adopt hammering pipe sinking method pipe sinking hole, then pour low-strength solid waste slurry, then pull out casing, form low-strength solid waste slurry pile;Steel pipe pile stiff core forms composite pile body, and the prefabricated micro steel pipe pile with body opening is pressed into low-strength solid waste slurry pile using static pressure method, and micro steel pipe pile and low-strength solid waste slurry pile form composite pile body together;Secondary grouting consolidates pile body, and using the body opening of micro steel pipe pile, strengthen solid waste grouting body is injected into low-strength solid waste slurry pile, and strengthen solid waste grouting splits, penetrates, solidifies low-strength solid waste slurry pile;The present application can improve bearing capacity and durability, save construction cost and can solve environmental problems.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of civil engineering, and particularly relates to a micro steel pipe pile reinforced core and solid waste combined strengthening grouting pipe sinking pile forming method. BACKGROUND

[0002] Soft soil refers to fine-grained soil with a natural void ratio greater than 1.0 and a natural water content greater than the liquid limit, including silt, silt soil, peat, peat soil, etc. Soft soil has the following characteristics: high natural water content, high void ratio, low shear strength, high compression coefficient, poor permeability, etc. The bearing capacity of soft soil foundation is low, and under the action of load, the foundation settlement deformation is large, and the uneven settlement is also large. Soft soil foundation is the most common soft foundation that needs to be treated in the field of engineering construction, and it is widely distributed in the coastal areas, both banks of rivers and lake areas in China. In the past, pipe sinking method was mainly used to make sand piles, and in recent years, it has been used to make gravel piles, which is a kind of compaction pile construction method. However, when the pipe sinking method is used repeatedly, the pile body necking phenomenon is easy to occur. Micro steel sheet pile is widely used in the treatment of soft soil foundation, but the vertical bearing capacity of single pile is limited, so there is still certain limitation in single foundation treatment technology.

[0003] With the development of national environmental protection policy and the proposal of the "carbon neutralization" goal, the solid waste (such as phosphorus tailings sand, iron tailings, etc.) generated by the previous industry has become a problem that needs to be solved urgently.

[0004] In view of this, a micro steel pipe pile reinforced core and solid waste combined strengthening grouting pipe sinking pile forming method is proposed. SUMMARY

[0005] In view of the deficiencies in the prior art, the present application provides a micro steel pipe pile reinforced core and solid waste combined strengthening grouting pipe sinking pile forming method which improves the bearing capacity and durability, saves construction cost and solves environmental problems.

[0006] The technical scheme of the present application is as follows: a micro steel pipe pile reinforced core and solid waste combined strengthening grouting pipe sinking pile forming method, comprising the following steps:

[0007] Pipe sinking grouting pile forming: using hammering pipe sinking method to form a hole, then pouring low-strength solid waste slurry, and then pulling out the sleeve to form a low-strength solid waste slurry pile;

[0008] Steel pipe pile reinforced core forms a composite pile body: using static pressure method to press the prefabricated micro steel pipe pile with holes around the body into the low-strength solid waste slurry pile, and the micro steel pipe pile and the low-strength solid waste slurry pile together form a composite pile body;

[0009] Secondary grouting and pile body reinforcement: using the holes around the body of the micro steel pipe pile to inject the reinforced solid waste slurry into the low-strength solid waste slurry pile, and the reinforced solid waste slurry performs splitting, penetration and solidification on the low-strength solid waste slurry pile.

[0010] The low-strength solid waste slurry comprises the following materials in mass fraction:

[0011] Low-strength cement 6-10 parts, iron tailings powder solid waste material 90-94 parts;

[0012] The water-solid ratio is 0.5-0.7, and the 7d unconfined compressive strength is 0.7-1.2 MPa.

[0013] The low-strength cement is cement with a strength grade of 32.5.

[0014] In the pipe sinking and grouting pile forming step, the reverse insertion method is used to form the pile, after waiting for the material in the pile to harden, the pipe sinking is reversed by half a circle to separate the pipe sinking from the pipe sinking bottom, and then the pipe sinking is taken out from the soil.

[0015] In the pipe sinking and grouting pile forming step, after being filled with the low-strength solid waste slurry, the casing pipe is vibrated and then pulled out, the casing pipe is pulled out by 0.5-1.0 m each time and then inserted by 0.3-0.5 m each time until the casing pipe is completely pulled out.

[0016] The reinforced solid waste grouting body comprises the following materials in mass fraction:

[0017] High-strength cement 35-50 parts, phosphorus tailings sand 50-65 parts;

[0018] The 7d unconfined compressive strength is 15-20 MPa.

[0019] The high-strength cement is cement with a strength grade of 42.5 or 52.5.

[0020] The upper end of the micro steel pipe pile is equipped with a rounded table type rubber plug, a grouting pipe and a pumping pipe.

[0021] In the secondary grouting and pile body reinforcing step, the reinforced solid waste grouting splits, penetrates and reinforces the soft soil outside the low-strength solid waste slurry pile.

[0022] The beneficial effects of the present application are:

[0023] (1) The micro steel pipe pile and solid waste combined reinforced grouting pipe sinking pile forming method in the present application is applied to the method for reinforcing soft soil, adopts the processes of forming a low-strength solid waste slurry pile by one-time grouting of pipe sinking, forming a composite pile body by a micro steel pipe pile and forming a pile body by secondary grouting of the steel pipe pile, realizes an effective soft soil reinforcing method by the low-strength solid waste slurry pile, the special micro steel pipe pile and the pressure grouting for reinforcing the pile body;

[0024] (2) The low-strength solid waste slurry pile is the outer structure, which plays a main protection and a secondary bearing role; the micro steel pipe pile is the intermediate structure, which plays a role of a core and bearing; the reinforced solid waste grouting is the inner structure, which plays a role of reinforcement and bearing, the three structures jointly form a composite pile, which has better compression resistance, shear resistance and other performances, is suitable for a weak foundation or a foundation needing to be reinforced, and improves the stability and bearing capacity of the foundation;

[0025] (3) The micro steel pipe pile of the core is protected by the inner and outer double solid waste slurry piles, can effectively prevent corrosion, improve durability, prolong service life, fully utilize solid waste resources, improve the utilization rate, and save construction cost;

[0026] (4) The micro steel pipe pile core forms a composite pile body, the prefabricated micro steel pipe pile with holes on the whole is pressed into the low-strength solid waste slurry pile of the first stage by using a static pressure method, the micro steel pipe pile is used as a core, and the low-strength solid waste slurry pile is used to form a composite pile body together, so that the necking problem of the pile body generated by the single pipe sinking method can be effectively improved, the pile body is more stable and firm, and the bearing capacity is improved;

[0027] (5) The twice solid waste slurry grouting can form good gradation and cementation, and the cement solidified composite soil is formed to solidify the soil layer around the pile. BRIEF DESCRIPTION OF DRAWINGS

[0028] Fig. 1 It is a method flow chart of the micro steel pipe pile core and solid waste combined reinforcement grouting pipe sinking pile forming method in the application.

[0029] Fig. 2 It is a method flow chart of the grouting of the pipe sinking grouting pile in the application.

[0030] Fig. 3 It is a method flow chart of the twice grouting in the application.

[0031] Fig. 4 It is one of the twice grouting schematic diagrams in the application.

[0032] Fig. 5 It is the second twice grouting schematic diagram in the application.

[0033] Fig. 6 It is a pile forming schematic diagram in the application. DETAILED DESCRIPTION

[0034] Various exemplary embodiments of the present application will now be described in detail with reference to the accompanying drawings. The description of the exemplary embodiments is only illustrative, and is not intended to be limiting on the present application and its applications or uses. The present application can be implemented in numerous ways, including but not limited to the embodiments described herein. These embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the application to those skilled in the art. It should be noted that the relative arrangement of components and steps, the components of materials, numerical expressions, and numerical values set forth in these embodiments are to be interpreted as merely exemplary, unless otherwise specifically stated, and not as a limitation.

[0035] The terms "first", "second", and similar terms in the present application do not denote any order, quantity, or importance, but are only used to distinguish different parts. The terms "comprise", "include", and similar terms mean that the elements before the term encompass the elements listed after the term, and do not exclude the possibility of also encompassing other elements. "Up", "down", "left", "right", and the like are only used to indicate relative positional relationships, and when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0036] As shown in Figs. 1 to 6 The micro steel pipe pile core and solid waste combined reinforced grouting pipe pile forming method includes the following steps:

[0037] Pipe pile grouting, using hammering pipe pile method to form hole, then pouring low-strength solid waste slurry, then pulling out the sleeve to form low-strength solid waste slurry pile;

[0038] Steel pipe pile core forms a composite pile body, the prefabricated micro steel pipe pile with holes around the body is pressed into the low-strength solid waste slurry pile using static pressure method, and the micro steel pipe pile and the low-strength solid waste slurry pile together form a composite pile body;

[0039] Secondary grouting reinforces the pile body, using the micro steel pipe pile with holes around the body to inject reinforced solid waste grouting into the low-strength solid waste slurry pile, and the reinforced solid waste grouting splits, penetrates, and solidifies the low-strength solid waste slurry pile;

[0040] The composite pile formed by the method of the micro steel pipe pile core and solid waste combined reinforced grouting in the embodiment is composed of a low-strength solid waste slurry pile, a micro steel pipe pile and reinforced solid waste grouting, which cooperates with each other to form a stable and high-strength composite pile body, and can effectively improve the bearing capacity and stability of the foundation. The low-strength solid waste slurry pile is the outer structure, which plays a main protection and secondary bearing role; the micro steel pipe pile is the intermediate structure, which plays a core and bearing role; the reinforced solid waste grouting is the inner structure, which plays a reinforcing and bearing role, and the three structures jointly form the composite pile, which has better compression resistance, shear resistance and other performances, is suitable for weak foundations or foundations that need to be reinforced, improves the stability and bearing capacity of the foundation; and the micro steel pipe pile core is protected by the inner and outer solid waste slurry piles, can effectively prevent corrosion, improve durability and prolong service life; at the same time, the composite pile type can fully utilize solid waste resources, improve the utilization rate, and improve the bearing capacity and durability of the pile body.

[0041] In the above embodiment, the pile forming by pipe-jacked grouting adopts the hammering pipe-jacking method to form a hole, a steel plate is used to block the pipe opening at the top of the pipe, a heavy hammer is lifted, then it is allowed to freely fall to impact the top of the pipe to generate vibration force, so as to sink the pipe into the soil layer; during the pipe sinking process, the pipe generates a certain lateral pressure on the original soil, so that the surrounding soil is forced to be laterally extruded, and the soil layer density within a certain range around the pile is improved.

[0042] In some embodiments, the low-strength solid waste slurry includes the following materials in mass fraction:

[0043] Low-strength cement 6-10 parts, iron tailings powder solid waste material 90-94 parts;

[0044] The water-solid ratio is 0.5-0.7, and the 7d unconfined compressive strength is 0.7-1.2MPa;

[0045] In the pile forming by pipe-jacked grouting step, the solid waste slurry absorbs water in the soil around the pile for hydration reaction, and the general experience mixing ratio is that the cement content is 6-10%. After the low-strength solid waste slurry is injected into the pile hole, the solid waste slurry absorbs water in the surrounding soil and simultaneously reacts with the cement to generate a certain amount of reaction heat, so that the water in the soil is solidified and the pore ratio is reduced, thereby increasing the density of the soil and the bearing capacity of the pile body; more specifically, the low-strength cement is a cement with a strength grade of 32.5.

[0046] In some embodiments, in the pile forming by pipe-jacked grouting step, the pile is formed by reverse insertion, after the material in the pile hardens, the pipe is rotated in the reverse direction by half a circle to separate it from the bottom of the pipe, and then the pipe is taken out of the soil.

[0047] In some embodiments, in the pipe-jacking pile-forming step, after filling the low-strength solid waste slurry, the casing is vibrated and then pulled out, the casing is pulled out by 0.5-1.0 m each time and then inserted back by 0.3-0.5 m, until the casing is completely pulled out, so as to eliminate or reduce the necking phenomenon.

[0048] In some embodiments, the reinforced solid waste slurry comprises the following materials in mass fraction:

[0049] high-strength cement 35-50 parts, phosphorus tailing sand 50-65 parts;

[0050] 7d unconfined compressive strength is 15MPa-20Mpa;

[0051] The micro steel pipe pile adopts a steel casing to form a hole, and then a secondary grouting slurry is filled in the hole, and the general experience mixing ratio is that the cement content is 35-50%; in construction, the steel pipe pile is pressed into the pile hole by using the static pressure method, the secondary grouting is carried out through the pressure grouting pipe at the top end of the steel pipe pile, until the pure slurry is poured out at the top of the pile; the reinforced solid waste slurry absorbs the water in the soil around the pile to carry out the hydration reaction, at this time, the water absorption, expansion and ion exchange of the grouting liquid and the primary grouting grouting material are mutually cemented, to form a more compact structure, so that the water content of the soil around the pile is reduced, the void ratio is reduced, the soil is compacted and the pile is hardened, the pile and the soil between the piles jointly bear the load, to become a kind of composite foundation; more specifically, the high-strength cement adopts cement with a strength grade of 42.5 or 52.5.

[0052] In some embodiments, the upper end of the micro steel pipe pile is equipped with a rounded table type rubber plug, a grouting pipe and a pumping pipe; the rounded table type rubber plug can prevent the grouting liquid from flowing back.

[0053] In some embodiments, in the secondary grouting pile-forming step, the reinforced solid waste slurry is injected into the low-strength solid waste slurry pile outside through the hole around the micro steel pipe pile, and the reinforced solid waste slurry splits, penetrates and reinforces the soft soil around the low-strength solid waste slurry pile.

[0054] So far, the embodiments of the present application have been described in detail. In order to avoid obscuring the concept of the present application, some details known in the art are not described. Those skilled in the art can fully understand how to implement the technical solutions disclosed herein according to the above description.

[0055] The above-described embodiments only express some implementation manners of the present application, and the description is more specific and detailed, but it should not be understood as a limitation on the scope of the patent. It should be pointed out that, for those skilled in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application should be subject to the appended claims.

Claims

1. A micro steel pipe pile reinforced by combined grouting of solid waste and core and pipe pile forming method, characterized in that, The method comprises the following steps: The pile is formed by pipe-jacking grouting, the pipe is formed by pipe-jacking hammering, then low-strength solid waste slurry is poured, and the pipe is pulled out to form a low-strength solid waste slurry pile; The steel pipe pile forms a composite pile body, a prefabricated micro steel pipe pile with holes on the whole body is pressed into the low-strength solid waste slurry pile by using a static pressure method, and the micro steel pipe pile and the low-strength solid waste slurry pile form a composite pile body together; The pile body is reinforced by secondary grouting, the reinforced solid waste slurry is injected into the low-strength solid waste slurry pile through the holes on the whole body of the micro steel pipe pile, and the reinforced solid waste slurry splits, penetrates and solidifies the low-strength solid waste slurry pile; The low-strength solid waste slurry comprises the following materials in mass fractions: 6-10 parts of low-strength cement and 90-94 parts of iron tailing powder solid waste material; The water-solid ratio is 0.5-0.7, and the 7d unconfined compressive strength is 0.7-1.2 MPa; In the pipe-jacking grouting pile forming step, the pile is formed by using a reverse insertion method, after the material in the pile is hardened, the pipe is rotated in the reverse direction by half a circle to separate the pipe from the bottom, and then the pipe is taken out of the soil; In the pipe-jacking grouting pile forming step, after the low-strength solid waste slurry is poured, the pipe is vibrated and then pulled out, the pipe is pulled out by 0.5-1.0 m and then inserted by 0.3-0.5 m in the reverse direction, until the pipe is completely pulled out; The reinforced solid waste slurry comprises the following materials in mass fractions: 35-50 parts of high-strength cement and 50-65 parts of phosphorus tailing sand; The 7d unconfined compressive strength is 15-20 MPa.

2. The method according to claim 1, wherein the method is characterized by: The low-strength cement is cement with a strength grade of 32.

5.

3. The method according to claim 1, wherein the method is characterized by: The high-strength cement is cement with a strength grade of 42.5 or 52.

5.

4. The method according to claim 1, wherein the method is characterized by: The upper end of the micro steel pipe pile is provided with a rounded table type rubber plug, a grouting pipe and a pumping pipe.

5. The method according to claim 1, wherein the method is characterized by: In the secondary grouting pile reinforcing step, the reinforced solid waste slurry splits, penetrates and reinforces the soft soil around the low-strength solid waste slurry pile.

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