阅读说明：本技术 一种新型高低压复合注浆施工工艺 (Novel high-low pressure composite grouting construction process ) 是由 袁建议 吴成皓 周逸 叶振沛 陈合龙 张定邦 于 2019-10-25 设计创作，主要内容包括：本发明公开了一种新型高低压复合注浆施工工艺,在注浆过程中,第一步采用低压模式将浆液以渗透的方式压入土体中,挤出土体中存在的自由水体,同时使浆液能够沿土体自身空隙通道充分填充软基中的空隙；第二步加大注浆压力,用高压模式使高压浆液进一步劈裂土体形成注浆通道达到注浆扩散半径设计要求；第三步采用低压模式,使浆液填充横竖交叉分布的空隙通道,形成水泥浆脉,达到注浆量效果,注浆完成后,水泥浆液与土体层形成符合路基强度要求的高强度和低压缩性的复合地基,从而达到加固软基的效果。本发明能够充分排出软基中的自由水；浆液充分渗透到软基空隙；复合地基承载力分布均匀；浆液设计扩散半径得到保证。(The invention discloses a novel high-low pressure composite grouting construction process, wherein in the grouting process, grout is pressed into a soil body in a low pressure mode in a permeating mode to extrude free water body existing in the soil body, and meanwhile, the grout can fully fill gaps in a soft foundation along a gap channel of the soil body; secondly, increasing grouting pressure, and enabling high-pressure slurry to further split a soil body to form a grouting channel in a high-pressure mode to meet the design requirement of grouting diffusion radius; and thirdly, a low-pressure mode is adopted, so that the grout fills the gap channels which are distributed in a transverse and vertical crossed manner to form cement mortar veins, the effect of grouting amount is achieved, and after grouting is finished, the cement grout and a soil body layer form a high-strength and low-compressibility composite foundation which meets the roadbed strength requirement, so that the effect of reinforcing the soft foundation is achieved. The invention can fully discharge free water in the soft foundation; the slurry fully permeates into the soft foundation gap; the bearing capacity of the composite foundation is uniformly distributed; the designed diffusion radius of the slurry is ensured.)

1. The novel high-low pressure composite grouting construction process is characterized by comprising the following construction steps:

A. checking whether barriers which hinder construction and influence safety exist at the designed hole site by contrasting with a design drawing before construction;

B. before construction, checking the quality of cement and admixture, the precision and sensitivity of pile position, pressure gauge and flowmeter, the proportion of grouting material and the performance of grouting high-pressure equipment;

C. lofting and positioning, arranging grouting holes in the field, driving bamboo piles or other markers into the holes, and ensuring the correct holes and the accurate distance between the holes, otherwise, slurry cannot be uniformly diffused to the reinforcing range;

D. placing a drilling machine in place, placing the drilling machine on a designed hole position, aligning the axis of a drill rod of the drilling machine to the center of a drill hole, and enabling the deviation between the drill hole position and the designed position to be less than 50 mm;

E. drilling, embedding a grouting pipe and sealing holes, firstly drilling to a designed depth by using an engineering geological drilling machine, wherein the hole diameter of the drilled hole is 91 or 101mm, immediately embedding a PVC grouting floral pipe to avoid hole blocking after the drilling is finished, fixing the grouting pipe to ensure that the grouting pipe is vertical and positioned at the hole center, and then pouring a cement-water glass mixture to seal the hole opening;

F. grouting, namely adopting a hole jumping grouting mode, firstly using low-pressure permeation grouting, paying attention to observing the surrounding situation of a grouting hole, when the grouting pump generates abnormal sound or the grout is blown out from an adjacent grouting pipe when the grout pressure is not fed in, immediately pressurizing the grout amount which does not reach single-hole grouting to high-pressure grouting pressure for 30-60 seconds, so that the grout splits a soil body to form a new grouting channel, and finally performing low-pressure continuous grouting until the designed grouting amount is reached or a large amount of grout is blown out from the adjacent hole position, wherein during high-pressure and low-pressure grouting, in order to ensure that the grout can be uniformly diffused to the whole reinforcing range, the hole positions on the plane need to be arranged in a quincunx manner;

G. the cleaning device is used, after the grouting operation is finished, the grouting hose is pulled out, the grouting pump sucks clear water to remove residual grout in the mud pump and the grouting hose, and the residual grout is prevented from blocking the pipeline.

2. The novel high-low pressure composite grouting construction process according to claim 1, characterized in that in step F, when the grouting amount is insufficient, the grout is ejected from the adjacent grouting pipe in advance, and when premature grout ejection occurs, the grouting pipe is blocked by a vacuum plastic bottle, and the grouting pressure is increased, so that the grout can be split off the soil body to form a new grouting channel, when the grouting amount is too large, if the soil is soft, the phenomenon is considered as normal, grouting can be continued until grout ejection occurs, and at this time, the actual grouting amount of a single hole is preferably controlled within 2 times of the theoretical grouting amount; when the grouting amount exceeds 2 times the theoretical grouting amount, no near-slip behavior is observed, and grouting should be stopped immediately.

3. The novel high-low pressure composite grouting construction process according to claim 1, wherein in step F, when grout cannot be injected, whether fine sand flows into the grouting pipe to block the grouting pipe is firstly checked, if the grouting pipe is blocked, a steel bar with a diameter smaller than that of the grouting pipe is immediately used for dredging so as not to cause the abandonment of a grouting hole, and when the high-low pressure grouting is finished or the grouting process is interrupted due to reasons, and the grouting pipe cannot be continuously sprayed within the initial setting time of the grout or less, the grouting pipe is immediately pulled out for cleaning and standby so as not to be pulled out after the grout is solidified.

Technical Field

The invention relates to a grouting construction process, in particular to a novel high-low pressure composite grouting construction process.

Background

The grouting treatment of the soft foundation of the highway subgrade is a treatment technology with feasible technology, good environmental protection and high economic benefit, the current specification is mainly divided into two processes of high-pressure grouting and low-pressure grouting, the research takes the grouting treatment of the soft foundation section of the highway as the engineering background, the field test shows that the single-form high-pressure grouting or low-pressure grouting can not ensure enough grout to be injected into the soil body, the ideal grouting effect is difficult to achieve, and the current specification of the single-pressure grouting process has the following defects: free water in the soft radical is difficult to completely discharge; filling the soft foundation gap with the slurry; the bearing capacity of the composite foundation is not uniform; the slurry diffusion radius does not meet the designed radius.

Disclosure of Invention

The technical problem to be solved by the invention is to overcome the defects of the prior art and provide a novel high-low pressure composite grouting construction process, which can fully discharge free water in a soft foundation; the slurry fully permeates into the soft foundation gap; the bearing capacity of the composite foundation is uniformly distributed; the designed diffusion radius of the slurry is ensured.

In order to solve the technical problems, the invention provides the following technical scheme:

the invention relates to a novel high-low pressure composite grouting construction process, which comprises the following construction steps:

A. checking whether barriers which hinder construction and influence safety exist at the designed hole site by contrasting with a design drawing before construction;

B. before construction, checking the quality of cement and admixture, the precision and sensitivity of pile position, pressure gauge and flowmeter, the proportion of grouting material and the performance of grouting high-pressure equipment;

C. lofting and positioning, arranging grouting holes in the field, driving bamboo piles or other markers into the holes, and ensuring the correct holes and the accurate distance between the holes, otherwise, slurry cannot be uniformly diffused to the reinforcing range;

D. placing a drilling machine in place, placing the drilling machine on a designed hole position, aligning the axis of a drill rod of the drilling machine to the center of a drill hole, and enabling the deviation between the drill hole position and the designed position to be less than 50 mm;

E. drilling, embedding a grouting pipe and sealing holes, firstly drilling to a designed depth by using an engineering geological drilling machine, wherein the hole diameter of the drilled hole is 91 or 101mm, immediately embedding a PVC grouting floral pipe to avoid hole blocking after the drilling is finished, fixing the grouting pipe to ensure that the grouting pipe is vertical and positioned at the hole center, and then pouring a cement-water glass mixture to seal the hole opening;

F. grouting, namely adopting a hole jumping grouting mode, firstly using low-pressure permeation grouting, paying attention to observing the surrounding situation of a grouting hole, when the grouting pump generates abnormal sound or the grout is blown out from an adjacent grouting pipe when the grout pressure is not fed in, immediately pressurizing the grout amount which does not reach single-hole grouting to high-pressure grouting pressure for 30-60 seconds, so that the grout splits a soil body to form a new grouting channel, and finally performing low-pressure continuous grouting until the designed grouting amount is reached or a large amount of grout is blown out from the adjacent hole position, wherein during high-pressure and low-pressure grouting, in order to ensure that the grout can be uniformly diffused to the whole reinforcing range, the hole positions on the plane need to be arranged in a quincunx manner;

G. the cleaning device is used, after the grouting operation is finished, the grouting hose is pulled out, the grouting pump sucks clear water to remove residual grout in the mud pump and the grouting hose, and the residual grout is prevented from blocking the pipeline.

As a preferred technical scheme of the invention, in the step F, when the grouting amount is insufficient, the grout is ejected from the adjacent grouting pipe in advance, and premature grout ejection occurs, the grouting pipe is blocked by the vacuum plastic bottle, and the grouting pressure is increased, so that the grout can be split off the soil body to form a new grouting channel, when the grouting amount is too large, if the soil is soft, the normal phenomenon is considered, grouting can be continued until grout ejection occurs, and at this time, the actual grouting amount of a single hole is preferably controlled within 2 times of the theoretical grouting amount; when the grouting amount exceeds 2 times the theoretical grouting amount, no near-slip behavior is observed, and grouting should be stopped immediately.

As a preferred technical solution of the present invention, when slurry cannot be injected in step F, it should be checked first whether fine sand flows into the grouting pipe to block the grouting pipe, if the grouting pipe is blocked, a steel bar with a diameter smaller than that of the grouting pipe is used immediately to dredge so as to avoid scrapping of a grouting hole, and when high-low pressure grouting is completed or the grouting process is interrupted due to reasons, and grouting cannot be continued within a time less than or equal to the initial setting time of slurry, the grouting pipe should be pulled out immediately for cleaning, so as to prevent the slurry from being pulled out after solidification.

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

1. fully discharging free water in the soft base;

2. the slurry fully permeates into the soft foundation gap;

3. the bearing capacity of the composite foundation is uniformly distributed;

4. the designed diffusion radius of the slurry is ensured.

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 view of the diffusion radius of the grouting slurry of the present invention;

FIG. 2 is a plan view of a grouting borehole of the present invention;

FIG. 3 is a flow diagram of a grouting process framework of the invention;

Detailed Description

The preferred embodiments of the present invention will be described in conjunction with the accompanying drawings, and it will be understood that they are described herein for the purpose of illustration and explanation and not limitation.