Deep hole grouting structure for earth surface of large-burial-depth water-rich fractured stratum and construction method

Abstract

The invention discloses a deep hole grouting structure for the earth surface of a large-burial-depth water-rich fractured stratum and a construction method, and relates to the technical field of underground engineering reinforcement. 2, grouting pipe laying construction is carried out, and at least three perforated grouting pipes with the lengths decreased progressively are coaxially arranged in a single hole; thirdly, step type grouting construction is conducted, the grouting time sequence of'bottom-up and top-thin and then thick 'is adopted, ground surface pumping reinforcing grout is diffused from grouting pipe holes through pressure difference, the broken stratum is consolidated, and stratum reinforcement is achieved; and fourthly, dynamic regulation and control are conducted, and grouting parameters are regulated and controlled based on real-time monitoring data. According to the deep hole grouting structure for the large-burial-depth water-rich fractured stratum earth surface and the construction method, a single-hole multi-pipe burying stepped graded injection mode is adopted, the grouting method has the characteristics of graded diffusion and multi-point injection, the diffusion range of grout is guaranteed, and the grouting reinforcement effect is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of underground engineering reinforcement, in particular to a deep-hole grouting structure and construction method for the surface of a large-buried deep water-rich broken stratum. BACKGROUND

[0002] The development of urban rail transit engineering has become an industry trend, among which subway, intercity, pipe gallery and other underground space operations are most common. When encountering complex strata, the surface drilling and buried grouting method is usually used, that is, a mechanical opening is made from the surface to the range of the stratum to be reinforced, a grouting pipe is buried in the pre-drilled hole, and a reinforcing slurry is pumped from the grouting pipe hole to implement diffusion by using pressure difference, so as to consolidate the broken stratum and achieve stratum reinforcement.

[0003] The present application is a multi-stage grouting pipe buried in the grouting hole in a large-buried deep water-rich broken stratum, which realizes graded injection and diffusion, avoids waste holes and poor reinforcement effect caused by single-hole single-pipe blockage, forms a multi-point injection and ladder diffusion grouting effect, and effectively improves stratum reinforcement.

[0004] The traditional surface deep-hole grouting process has the following defects: single-pipe grouting in water-rich strata is prone to pipe blockage due to rapid slurry solidification, and the utilization rate of the hole is less than 60%; the slurry diffusion in broken strata is anisotropic, and single-point grouting is prone to local enrichment and uneven overall reinforcement; under the condition of large buried depth, the grouting pressure decays significantly, and the effective diffusion radius is only 40-70% of the design value. SUMMARY

[0005] In view of the deficiencies of the prior art, the present application provides a deep-hole grouting structure and construction method for the surface of a large-buried deep water-rich broken stratum, which solves the problems raised in the background art.

[0006] To achieve the above purpose, the present application realizes the following technical scheme: a construction method for deep-hole grouting for the surface of a large-buried deep water-rich broken stratum, comprising the following specific steps:

[0007] Step 1: surface deep drilling construction;

[0008] Step 2: grouting pipe layout construction, at least 3 coaxial grouting pipes with decreasing lengths are arranged in a single hole;

[0009] Step 3: ladder grouting construction, using the grouting time sequence of "first down then up, first dilute then thick", pumping reinforcing slurry from the grouting pipe hole to implement diffusion by using pressure difference, consolidating the broken stratum, and achieving stratum reinforcement;

[0010] Step 4: dynamic regulation and control, regulating and controlling the grouting parameters based on real-time monitoring data using the following formula,

[0011] Q=β*k*(P maxP0) / μ*ln(R / r0)

[0012] Wherein, β is the formation broken correction coefficient (1.2-1.8), k is the permeability coefficient.

[0013] Optionally, the step one of the ground deep hole drilling tool body is as follows:

[0014] (1) using Φ150-200mm drill bit vertical drilling to the reinforced zone bottom plate below 2m;

[0015] (2) real-time record core broken degree RQD value, when RQD<40%, mark for strengthening grouting section.

[0016] Optionally, the step two of the opening grouting pipe is preferably Φ32, Φ42, Φ60mm combination.

[0017] Optionally, the step two of the grouting pipe is configured in stages:

[0018] Primary pipe (bottom pipe): opening rate 30%, aperture 8mm, arranged in the lowermost layer of reinforced zone;

[0019] Secondary pipe (middle pipe): opening rate 20%, aperture 6mm, with check valve;

[0020] Tertiary pipe (upper pipe): opening rate 15%, aperture 5mm, outer winding fiber filter screen.

[0021] Optionally, the step three of the ladder type grouting tool body is as follows:

[0022] (1) the first level pipe is injected with ultra-fine cement slurry with water-cement ratio of 1:1-1.2, pressure 0.8-1.2MPa, lasting 30min;

[0023] (2) the second level pipe is injected with double liquid slurry added with 3%water glass, pressure 1.5-2.0MPa;

[0024] (3) the third level pipe is injected with thickened slurry liquid mixed with bentonite, pressure 2.5-3.0MPa.

[0025] Optionally, the step four of the monitoring data includes flow, pressure, ground uplift.

[0026] The deep hole grouting structure for the ground of the deep buried water-rich broken formation, comprising a plurality of ground deep holes, and the ground deep holes are parallel to each other;

[0027] The ground deep hole penetrates the ground from top to bottom and extends to the broken formation below;

[0028] The grouting pipeline is provided with a plurality of grouting holes.

[0029] The grouting pipe sealing pipe is arranged outside the grouting pipe.

[0030] Optionally, the plurality of grouting pipes are parallel to each other.

[0031] Optionally, three or more grouting pipes are inserted into each deep ground hole.

[0032] Optionally, the outer edge of the grouting pipe sealing pipe is attached to the inner wall of the deep ground hole.

[0033] The present application provides a deep hole grouting structure and construction method for the surface of a large buried depth water-rich broken stratum, which has the following beneficial effects:

[0034] The deep hole grouting structure and construction method for the surface of a large buried depth water-rich broken stratum, through the multi-pipe redundancy design, when a grouting pipe is blocked, the remaining pipes can still work, the system fault tolerance is improved by 300%, the actual engineering data shows that under the same geological conditions, the hole forming effective utilization rate of the method reaches 92.3%, which is significantly improved compared with the traditional method, the geological radar detection shows that the grout distribution variation coefficient of the reinforced area is reduced from 0.68 of the traditional method to 0.41, and the uniformity is improved by 39.7%; through the multi-pipe shunting and step-by-step pressure boosting strategy, the pressure loss is reduced: under the condition of 68m buried depth, the measured bottom pressure is 87.6% of the surface pump pressure (the traditional method is only 52.3%); when the same reinforcement amount is completed, the power consumption of the present application is only 2.1kW·h / m 3 , which is 38.2% lower than that of the traditional method (3.4kW·h / m 3 ). BRIEF DESCRIPTION OF DRAWINGS

[0035] Figure 1 It is a front view structural schematic diagram of the present application;

[0036] Figure 2 It is an enlarged structural schematic diagram of the grouting pipe in the present application;

[0037] Figure 3 It is a schematic diagram of the conventional grouting pipe distribution.

[0038] In the figure: 1, deep ground hole; 2, grouting pipe; 3, grouting hole; 4, broken stratum; 5, grouting pipe sealing pipe. DETAILED DESCRIPTION

[0039] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, not all the embodiments.

[0040] In the description of the present application, unless otherwise specified, the meaning of "a plurality of" is two or more; the orientation or positional relationship indicated by the terms "upper", "lower", "left", "right", "inner", "outer", "front end", "rear end", "head", "tail" and the like is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first", "second", "third" and the like are only for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0041] In the description of the present application, it should be noted that, unless otherwise specified and limited, the terms "connected", "connected" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0042] The construction method for deep hole grouting of the surface of a large buried depth water-rich broken stratum comprises the following specific steps:

[0043] Step one: deep hole drilling construction on the surface, specifically as follows:

[0044] (1) a Φ150-200mm drill bit is used to drill vertically to a position 2m below the bottom plate of the reinforcement area;

[0045] (2) the core fragmentation degree RQD value is recorded in real time, and when RQD < 40%, it is marked as a strengthening grouting section;

[0046] Step two: grouting pipe layout construction, at least three length-decreasing open-hole grouting pipes are coaxially laid in a single hole, and the open-hole grouting pipes are preferably a combination of Φ32, Φ42 and Φ60mm;

[0047] Grouting pipe grading:

[0048] Primary pipe (bottom pipe): 30% open hole rate, 8mm hole diameter, arranged in the lowermost layer of the reinforcement area;

[0049] Secondary pipe (middle pipe): 20% open hole rate, 6mm hole diameter, with a check valve;

[0050] Tertiary pipe (upper pipe): 15% open hole rate, 5mm hole diameter, wrapped with a fiber filter screen;

[0051] Step three: ladder grouting construction, using the grouting timing of "first down then up, first dilute then thick", surface pumping consolidation slurry diffuses from the grouting pipe hole using pressure difference to consolidate the broken stratum, and realizes stratum reinforcement, which is as follows:

[0052] (1) The superfine cement slurry with water-cement ratio of 1:1-1.2 is injected into the first-stage pipe, the pressure is 0.8-1.2 MPa, and the duration is 30 min;

[0053] (2) The double-liquid slurry with 3% water glass is injected into the second-stage pipe, the pressure is 1.5-2.0 MPa;

[0054] (3) The thickened slurry with bentonite is injected into the third-stage pipe, the pressure is 2.5-3.0 MPa;

[0055] Step four: dynamic regulation and control, the grouting parameters are regulated and controlled based on real-time monitoring data, and the monitoring data includes flow, pressure, and surface uplift;

[0056] Q=β*k*(P max -P0) / μ*ln(R / r0)

[0057] Wherein, β is a broken stratum correction coefficient (1.2-1.8), and k is a permeability coefficient.

[0058] Please refer to Figures 1 to 3 , the application provides a technical scheme: a deep-hole grouting structure and construction method for the surface of a large-buried-depth broken stratum rich in water, comprising a plurality of surface deep holes 1, wherein the surface deep holes 1 are parallel to each other.

[0059] The surface deep holes 1 penetrate the surface from top to bottom and extend to the broken stratum 4 below.

[0060] The grouting pipe 2 is provided with a plurality of grouting holes 3 on the surface.

[0061] The grouting pipe sealing pipe 5 is sleeved outside the grouting pipe 2.

[0062] In this embodiment, as shown in Figure 1 , the plurality of grouting pipes 2 are parallel to each other.

[0063] In this embodiment, as shown in Figure 1 , three or more grouting pipes 2 are inserted into each surface deep hole 1.

[0064] In this embodiment, as shown in Figure 1 , the outer edge of the grouting pipe sealing pipe 5 is attached to the inner wall of the surface deep hole 1.

[0065] Table 1 Comparison test data of hole utilization rate (a certain sandstone broken zone project)

[0066] Method Total number of drill holes Number of effective grouting holes Utilization rate Single-tube grouting 120 70 58.3％ Multi-tube grouting 120 111 92.3％

[0067] Conclusion: The slurry diffusion uniformity is improved by 40%, and three progressive diffusion circles are formed through the step pressure control (0.8→2.8 MPa) and the hierarchical opening design:

[0068] Primary grouting: The slurry penetrates along the main fissure network (diffusion radius R1=3.2±0.5 m);

[0069] Secondary grouting: The secondary fissure is filled under the action of medium pressure (R2=2.1±0.3 m);

[0070] Tertiary grouting: The small pores are extruded by high pressure (R3=1.5±0.2 m).

[0071] The above merely describes the preferred specific embodiments of the present application, but the protection scope of the present application is not limited thereto, and any person skilled in the art can make equivalent replacements or changes according to the technical scheme and the inventive concept of the present application within the technical range disclosed by the present application, which should be covered within the protection scope of the present application.

Claims

1. A construction method for deep-hole grouting on the surface of deep, water-rich, fractured strata, characterized in that: The specific steps include the following: Step 1: Deep surface drilling; Step 2: Grouting pipe installation: At least 3 grouting pipes of decreasing length are coaxially installed in a single hole. Step 3: Step-by-step grouting construction, adopting the grouting sequence of "bottom first, then top, thin first, then thick". The surface pumped reinforcement grout diffuses through the grouting pipe holes using pressure difference to consolidate the fractured strata and achieve stratum reinforcement. Step 4: Dynamic control. Based on real-time monitoring data, the grouting parameters are adjusted using the following formula: Q=β*k*(P max -P0) / μ*ln(R / r0) Where β is the formation fracturing correction factor (1.2-1.8) and k is the permeability coefficient.

2. The construction method for deep-hole grouting on the surface of deep-buried, water-rich, fractured strata according to claim 1, characterized in that: The specific details of the deep surface drilling construction in step one are as follows: (1) Use a Φ150-200mm drill bit to drill vertically to a depth of 2m below the bottom plate of the reinforced area; (2) Record the core fragmentation RQD value in real time. When RQD < 40%, mark it as an enhanced grouting section.

3. The construction method for deep-hole grouting on the surface of deep-buried, water-rich, fractured strata according to claim 1, characterized in that: The preferred combination of Φ32, Φ42, and Φ60mm is used for the grouting pipe in step two.

4. The construction method for deep-hole grouting on the surface of deep-buried, water-rich, fractured strata according to claim 1, characterized in that: The graded configuration of grouting pipes in step two: Primary pipe (bottom pipe): 30% opening rate, 8mm hole diameter, arranged in the lowest layer of the reinforced area; Secondary tube (middle tube): 20% opening ratio, 6mm orifice diameter, with check valve; Three-stage tube (upper tube): 15% opening rate, 5mm pore size, externally wrapped with fiber filter screen; The distance between the bottom ends of the tertiary pipe and the secondary pipe is the same as the distance between the bottom ends of the secondary pipe and the primary pipe.

5. The construction method for deep-hole grouting on the surface of deep-buried, water-rich, fractured strata according to claim 1, characterized in that: The specific details of the stepped grouting construction in step three are as follows: (1) Inject ultrafine cement slurry with a water-cement ratio of 1:1-1.2 into the primary pipe, with a pressure of 0.8-1.2 MPa, for 30 minutes; (2) Inject a two-component slurry with 3% water glass into the secondary tube at a pressure of 1.5-2.0 MPa; (3) Inject thickened slurry mixed with bentonite into the three-stage pipe at a pressure of 2.5-3.0 MPa.

6. The construction method for deep-hole grouting on the surface of deep-buried, water-rich, fractured strata according to claim 1, characterized in that: The monitoring data in step four includes flow rate, pressure, and land uplift.

7. A deep-hole grouting structure for use in any one of claims 1 to 6 for deep-buried, water-rich, fractured strata, comprising a deep-hole at the surface (1), characterized in that: The surface deep boreholes (1) are provided in multiple ways and are parallel to each other; The deep surface borehole (1) penetrates the surface from top to bottom and extends to the fractured strata (4) below it; The grouting pipe (2) is provided with multiple grouting pipes (2), and multiple grouting holes (3) are opened on the surface of the grouting pipe (2); The grouting pipe sealing pipe (5) is fitted outside the grouting pipe (2).

8. The deep-hole grouting structure for the surface of deep-buried, water-rich, fractured strata according to claim 7, characterized in that: The multiple grouting pipes (2) are parallel to each other.

9. The deep-hole grouting structure for the surface of deep-buried, water-rich, fractured strata according to claim 7, characterized in that: Each of the aforementioned deep surface boreholes (1) contains three or more grouting pipes (2).

10. The deep-hole grouting structure for the surface of deep-buried, water-rich, fractured strata according to claim 7, characterized in that: The outer edge of the grouting pipe sealing pipe (5) is fitted with the inner wall of the deep surface hole (1).

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