阅读说明：本技术 钉形水泥土双向搅拌桩施工工艺 (Nail-shaped cement soil bidirectional mixing pile construction process ) 是由 陈超 苏辉 于 2020-04-20 设计创作，主要内容包括：本发明属于钉形水泥土双向搅拌桩施工技术领域,尤其为钉形水泥土双向搅拌桩施工工艺,包括如下步骤：搅拌机就位,搅拌机到指定桩位并对中,喷浆下沉：启动搅拌机,使搅拌机沿导向架向下切土,同时开启送浆泵向土体喷水泥浆,两组叶片同时正、反向旋转(外钻杆逆时针旋转,内钻杆顺时针旋转)切割搅拌土体,搅拌机持续下沉,直到扩大头设计深度,改变内、外钻杆的旋转方向,将搅拌叶片收缩到下部桩体直径；通过外杆上叶片反向旋转过程中的压浆作用和正反向旋转叶片同时双向搅拌水泥土的作用,阻断水泥浆上冒,把水泥浆控制在两组叶片之间,保证水泥浆在桩体中均匀分布和搅拌均匀,确保成桩质量。(The invention belongs to the technical field of nail-shaped cement soil bidirectional mixing pile construction, in particular to a nail-shaped cement soil bidirectional mixing pile construction process, which comprises the following steps: the mixer takes one's place, and the mixer is to appointed stake position and centering, and the whitewashing sinks: starting the stirrer to cut soil downwards along the guide frame, simultaneously starting the slurry feeding pump to spray cement slurry to the soil body, simultaneously rotating the two groups of blades forwards and backwards (the outer drill rod rotates anticlockwise, the inner drill rod rotates clockwise) to cut the stirred soil body, continuously sinking the stirrer until the designed depth of the enlarged head is reached, changing the rotating direction of the inner drill rod and the outer drill rod, and contracting the stirring blades to the diameter of the lower pile body; the grouting effect of the blades on the outer rod in the reverse rotation process and the effect of bidirectional stirring of cement soil by the forward and reverse rotating blades simultaneously block the upward overflow of cement paste, the cement paste is controlled between the two groups of blades, the uniform distribution and the uniform stirring of the cement paste in a pile body are ensured, and the pile forming quality is ensured.)

1. The nail-shaped cement soil bidirectional mixing pile construction process is characterized in that: the method comprises the following steps:

s1, positioning a stirrer, and centering the stirrer to the designated pile position;

s2, spraying and sinking: starting the stirrer to cut soil downwards along the guide frame, simultaneously starting the slurry feeding pump to spray cement slurry to the soil body, simultaneously rotating the two groups of blades forwards and backwards (the outer drill rod rotates anticlockwise, the inner drill rod rotates clockwise) to cut and stir the soil body, and continuously sinking the stirrer until the designed depth of the expansion head is reached;

s3, constructing a lower pile body: changing the rotating direction of the inner drill rod and the outer drill rod, and contracting the stirring blades to the diameter of the lower pile body; the guniting soil cutting sinks, the two groups of blades rotate forwards and backwards to cut and stir the soil body at the same time, the stirrer sinks continuously until the designed depth, and the guniting stirring is continuously carried out on the pile end for more than 10 seconds;

s4, lifting and stirring: the stirring machine lifts and closes the slurry feeding pump, and the two groups of blades rotate forward and backward simultaneously to stir the cement soil until the bottom surface elevation of the enlarged head is reached;

s5, stretching the blade: changing the rotating direction of the inner and outer drill rods, and extending the stirring blades to enlarge the head diameter; lifting and stirring, lifting a drill rod and two groups of blades, and simultaneously rotating and stirring the cement soil in forward and reverse directions until the elevation of the ground surface or the designed pile top is 50cm higher;

s6, cutting soil and sinking: the mixer cuts soil downwards along the guide frame, simultaneously starts a slurry feeding pump, sprays cement slurry to the soil body, the two groups of blades rotate forwards and backwards to cut and mix the soil body simultaneously, and the mixer sinks continuously until the designed depth of the expansion head is reached;

s7, lifting and stirring: and (5) closing the slurry feeding pump, and simultaneously rotating and stirring the cement soil by the two groups of blades in the forward and reverse directions until the elevation of the ground surface or the designed pile top is 50cm higher, so that the single-pile construction is completed.

2. The nail-shaped cement soil bidirectional mixing pile construction process according to claim 1, characterized in that: the sinking speed in the steps S2, S3 and S6 is 0.5-0.8m/min, and the guniting pressure during sinking is 0.25-0.40 MPa.

3. The nail-shaped cement soil bidirectional mixing pile construction process according to claim 1, characterized in that: the lifting speed in step S4, step S5, and step S7 is 0.7-1.0 m/min.

4. The nail-shaped cement soil bidirectional mixing pile construction process according to claim 1, characterized in that: in step S2, the rotating speed of the inner drill rod is more than or equal to 50r/min, and the rotating speed of the outer drill rod is more than or equal to 70 r/min.

5. The nail-shaped cement soil bidirectional mixing pile construction process according to claim 1, characterized in that: the blade width in step S2-step S7 is 80-100 mm; the thickness of the blade is 25-40 mm; the blade angle is 10-20 degrees.

Technical Field

The invention belongs to the technical field of nail-shaped cement soil bidirectional mixing pile construction, and particularly relates to a nail-shaped cement soil bidirectional mixing pile construction process.

Background

The cement mixing pile is an effective form of soft foundation treatment, and is characterized by that it uses cement as main agent of solidifying agent, and utilizes mixing pile machine to spray cement into soil body and fully mix them so as to make cement and soil produce a series of physical and chemical reactions, and make the soft soil be hardened and raise foundation strength. The cement mixing pile is divided into single-shaft, double-shaft and three-shaft mixing piles according to the construction method mainly used. In the 70 s of the 20 th century, the cement mixing piles are used for reinforcing soft soil foundations, and the history of more than 40 years is existed so far. The method is to forcibly stir the soft soil and the cement (curing agent) by a special deep layer stirrer, and solidify the soil body by utilizing a series of physical and chemical reactions generated between the cement and the soft soil to form the cement soil pile with integrity, water stability and certain strength. The process is mainly used for treating soft soil foundations.

The pile-forming machine of nail-shaped cement soil bidirectional mixing pile is to improve the power transmission system, drill rod and drill bit of the existing cement soil mixing pile-forming machine, concentric double-shaft drill rod is adopted, the inner drill rod is provided with forward rotating blades and a slurry spraying port, the outer drill rod is provided with reverse rotating blades, the slurry overflow on the cement slurry is blocked by the slurry pressing effect in the reverse rotating process of the blades on the outer drill rod and the effect of the forward and reverse rotating blades on bidirectional mixing cement soil at the same time, the cement slurry is controlled between the two groups of blades, the uniform distribution and uniform mixing of the cement slurry in the pile body are ensured, and the pile-forming quality is ensured; meanwhile, the stirring blade is set to be a telescopic blade (note: the blade can be telescopic at any depth below the ground) so as to facilitate the construction of the pile body with different sections on the upper and lower sides of the cement-soil stirring pile. The nail-shaped cement soil bidirectional mixing pile is a cement soil mixing pile which is similar to a nail shape and is formed by expanding the section of the upper part of a pile body through the expansion and contraction of a mixing blade.

In the current construction process of the nail-shaped cement soil bidirectional mixing pile, the condition of overflowing of cement paste is easy to occur, so that the construction environment is not easy to clean, and meanwhile, the cement paste is unevenly distributed in the pile body, thereby influencing the pile forming quality.

Therefore, the technical field provides a nail-shaped cement soil bidirectional mixing pile construction process to solve the problems in the background.

Disclosure of Invention

To solve the problems set forth in the background art described above. The invention provides a nail-shaped cement soil bidirectional mixing pile construction process which has the characteristics of simple and convenient operation in the construction process, safe and stable construction site, good construction environment and high pile forming quality.

In order to achieve the purpose, the invention provides the following technical scheme: the nail-shaped cement soil bidirectional mixing pile construction process comprises the following steps:

s1, positioning a stirrer, and centering the stirrer to the designated pile position;

s2, spraying and sinking: starting the stirrer to cut soil downwards along the guide frame, simultaneously starting the slurry feeding pump to spray cement slurry to the soil body, simultaneously rotating the two groups of blades forwards and backwards (the outer drill rod rotates anticlockwise, the inner drill rod rotates clockwise) to cut and stir the soil body, and continuously sinking the stirrer until the designed depth of the expansion head is reached;

s3, constructing a lower pile body: changing the rotating direction of the inner drill rod and the outer drill rod, and contracting the stirring blades to the diameter of the lower pile body; the guniting soil cutting sinks, the two groups of blades rotate forwards and backwards to cut and stir the soil body at the same time, the stirrer sinks continuously until the designed depth, and the guniting stirring is continuously carried out on the pile end for more than 10 seconds;

s4, lifting and stirring: the stirring machine lifts and closes the slurry feeding pump, and the two groups of blades rotate forward and backward simultaneously to stir the cement soil until the bottom surface elevation of the enlarged head is reached;

s5, stretching the blade: changing the rotating direction of the inner and outer drill rods, and extending the stirring blades to enlarge the head diameter; lifting and stirring, lifting a drill rod and two groups of blades, and simultaneously rotating and stirring the cement soil in forward and reverse directions until the elevation of the ground surface or the designed pile top is 50cm higher;

s6, cutting soil and sinking: the mixer cuts soil downwards along the guide frame, simultaneously starts a slurry feeding pump, sprays cement slurry to the soil body, the two groups of blades rotate forwards and backwards to cut and mix the soil body simultaneously, and the mixer sinks continuously until the designed depth of the expansion head is reached;

s7, lifting and stirring: and (5) closing the slurry feeding pump, and simultaneously rotating and stirring the cement soil by the two groups of blades in the forward and reverse directions until the elevation of the ground surface or the designed pile top is 50cm higher, so that the single-pile construction is completed.

Preferably, the sinking speed in step S2, step S3 and step S6 is 0.5-0.8m/min, and the guniting pressure during sinking is 0.25-0.40 MPa.

Preferably, the lifting speed in step S4, step S5, and step S7 is 0.7-1.0 m/min.

Preferably, the rotating speed of the inner drill rod is equal to or more than 50r/min, and the rotating speed of the outer drill rod is equal to or more than 70r/min in step S2.

Preferably, the width of the blade in the steps S2-S7 is 80-100 mm; the thickness of the blade is 25-40 mm; the blade angle is 10-20 degrees.

Compared with the prior art, the invention has the beneficial effects that:

through establishing two sets of blades into positive and negative rotation, when starting up the mixer, make the mixer cut soil along the leading truck downwards, open the slurry feeding pump simultaneously and spout grout to the soil body, two sets of blades are simultaneously positive, the contrarotation (outer drilling rod counter-clockwise turning, interior drilling rod clockwise turning) cuts the stirring soil body, the mixer continues to sink, until the enlarged footing design depth, through the mud jacking effect of outer pole upper blade contrarotation in-process and the effect of positive and negative rotation blade two-way stirring soil cement simultaneously, block and emit on the grout, control grout between two sets of blades, guarantee grout evenly distributed and stirring in the pile body, ensure to become the stake quality.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention and not to limit the invention. In the drawings:

FIG. 1 is a schematic structural view of a nail-shaped cement soil bidirectional mixing pile construction process of the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.