A method for strengthening a slope through a drainage channel

Abstract

The present invention discloses a method for strengthening a slope through a drainage channel. The method is as follows: determine the layout characteristics of the drainage channel on the cross-section of the slope, determine the inner diameter of the non-permeable foamed concrete hollow beam according to the rainfall characteristics of the location where the slope is located, determine the outer diameter of the non-permeable foamed concrete hollow beam according to the strength of the non-permeable foamed concrete, determine the length and diameter of the permeable foamed concrete beam according to the requirement of discharging free water in the slope, and carry out inclined jet grouting construction of the non-permeable foamed concrete hollow beam on the slope by using the jet grouting pile construction method according to the layout characteristics and the outer diameter of the non-permeable foamed concrete hollow beam. Drill holes along the axis according to the inner diameter on the non-permeable foamed concrete jet grouting pile to obtain the non-permeable foamed concrete hollow beam, and fill the permeable foamed concrete into the hollow beam. The present invention can strengthen the slope while naturally discharging the water of the phreatic line in the slope, and has very good application prospects.

Description

Technical Field

[0001] The present invention belongs to the field of slope drainage and slope reinforcement, and particularly relates to a method for reinforcing slopes through drainage channels. Background Art

[0002] Foamed concrete is mostly used for subgrade filling, slope protection, and insulation walls. Foamed concrete has the characteristics of low cost, low density, heat preservation and insulation. When applied to subgrade filling and slope protection, it can reduce the soil load, thereby reducing building settlement and improving building stability.

[0003] The main slope drainage methods include setting drainage ditches, drainage tunnels, drainage holes, etc. These methods have been widely used in slope drainage engineering practices at home and abroad. Slope reinforcement mainly adopts methods such as grouting, anchor rods, soil nails, prestressed anchor cables, etc.

[0004] Currently, there has been research on draining slopes using the water head difference. For example, a patent for a slope drainage device (publication number: 216108549U) uses the water head difference and siphon action to drain the slope through a drainage pipe. However, the drainage pipe used in this patent is prone to aging, especially in the complex environment inside the slope, and has a short service life. In addition, this patent can only play a drainage role, not only unable to reinforce the slope, but also disturbing the slope during the implementation of this patent, increasing the risk of slope instability and landslide. In engineering, there is also a method of draining water using drainage holes, such as a patent for a slope active drainage method and device (publication number: 113152492A). This patent drains water by means of a fan exhausting air. Therefore, it can only drain a small amount of water in the gaseous state, with a small drainage volume. Moreover, the operation of the fan and the main controller, which play a key role, only rely on solar power supply, which is greatly affected by climate factors, inconvenient for energy storage, and in the case of rain when drainage is required, solar energy cannot supply power, so the applicable working conditions are few. In addition, the method of setting drainage holes and the placement angle in this patent are not conducive to slope stability and are prone to causing landslides. Therefore, a drainage method with a long service life, capable of naturally draining the water of the phreatic line inside the slope and reinforcing the slope is needed, and the key point of this drainage method is to effectively utilize the water head difference to naturally drain water while reinforcing the slope. Summary of the Invention

[0005] The purpose of the present invention is to provide a method for reinforcing slopes through drainage channels, aiming to solve the problem that the existing construction methods cannot effectively solve the problems of slope drainage and reinforcement at the same time.

[0006] The present invention is realized as follows. A method for reinforcing slopes through drainage channels, the drainage channel is composed of a non-permeable foamed concrete hollow beam and a permeable foamed concrete filling the inside of the hollow beam, and the drainage channel is arranged inside the slope from the slope surface; the method includes the following steps:

[0007] (1) Determine the layout characteristics of the drainage channels on the slope cross section, including the number n, the length L1 of the non-permeable foam concrete hollow beam, the inclination angle θ, the drilling position, and the longitudinal drainage channel spacing d of the slope;

[0008] (2) Determine the inner diameter r of the non-permeable foam concrete hollow beam according to the rainfall characteristics of the slope location, and determine the outer diameter R1 of the non-permeable foam concrete hollow beam according to the strength of the non-permeable foam concrete;

[0009] (3) Determine the length L2 and diameter R2 of the permeable foam concrete beam according to the free water drainage requirements in the slope, where the diameter R2 is equal to the inner diameter r;

[0010] (4) According to the layout characteristics and the outer diameter R1 of the non-permeable foam concrete hollow beam, the non-permeable foam concrete hollow beam is constructed on the slope using a rotary jet pile construction method;

[0011] (5) After the non-permeable foam concrete has initially set, a hole is drilled on the non-permeable foam concrete jet-jet pile along the axis according to the inner diameter r in step (3) to obtain a non-permeable foam concrete hollow beam, and the hollow beam is filled with permeable foam concrete with a permeability coefficient K and a length L2.

[0012] Preferably, in step (1), determining the layout characteristics of the drainage channel includes the following steps:

[0013] (1-1) Determine the maximum 24-hour rainfall h at the slope location max , the number of drainage channels n on the slope cross section is determined by the following formula:

[0014]

[0015] Among them, h1 and h3 represent the 24-hour rainfall limit values;

[0016] (1-2) Determine the location of the drill hole at the foot of the slope and its elevation from the bottom of the slope;

[0017] (1-3) Determine the inclination angle θ of each drainage channel with a borehole located at the slope toe and the length L1 of the non-permeable foam concrete hollow beam of each drainage channel. L1 places the end of the non-permeable foam concrete hollow beam at a higher water head in the seepage field. Furthermore, θ minimizes the distance between the borehole of the non-permeable concrete pile and the infiltration line, provided that the intersection of the equipotential line and the infiltration line at the end of the hollow beam is at least 1 m above the slope bottom.

[0018] (1-4) Determine the longitudinal drainage channel distance d of the slope.

[0019] Preferably, in step (2), the cross-sectional inner diameter r is determined by the following formula:

[0020]

[0021] The outer diameter R1 is determined by the following formula:

[0022]

[0023] where α and β are constant coefficients, and the outer diameter is determined according to the inner diameter of the cross-section.

[0024] Preferably, in step (3), the length L2 = L1 + 0.2 m;

[0025] Taking the ground as the reference plane, the seepage head at the end of the impervious foam concrete pile is:

[0026]

[0027] where z is the position head / m, P is the groundwater pressure / kPa, and γ w is the unit weight of water / kN / m 3 ;

[0028] The head h at the top of the impervious foam concrete sl2 = 0.1 m.

[0029] Preferably, in step (5), the preparation process of the permeable foam concrete with the permeability coefficient K includes the following steps:

[0030] Mix 446 kg of cement, 125 kg of water, and 179 kg of sand to form a slurry;

[0031] Mix the foaming agent and water in a mass ratio of 1:40 to obtain a foaming liquid, and add 650 L of the foaming liquid to the slurry, and stir evenly slowly to obtain the permeable foam concrete with the permeability coefficient K.

[0032] Compared with the disadvantages and deficiencies of the prior art, the present invention has the following beneficial effects:

[0033] (1) The present invention can reinforce the slope while naturally discharging the water in the slope of the phreatic line;

[0034] (2) Compared with ordinary PVC drain pipes, the present invention has a longer service life and is anti-blocking;

[0035] (3) The present invention has a low cost, simple and convenient construction, and has a very good application prospect. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 is a schematic structural diagram of the drainage channel of the present invention;

[0037] Figure 2It is a schematic cross-sectional view of the drainage channel arrangement of the present invention behind the slope;

[0038] Figure 3 It is a front view of the drainage channel arrangement of the present invention on the slope;

[0039] Figure 4 It is Figure 3 A marked diagram of the relevant parameters after the layout of each structure in Detailed implementation manners

[0040] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0041] An embodiment of the present invention discloses a method for strengthening a slope through a drainage channel. The drainage channel, as Figure 1 shown, is composed of a non-permeable foam concrete hollow beam and a permeable foam concrete filling the inside of the hollow beam. The drainage channel, as Figure 2 shown, is arranged inside the slope from the slope surface; combining Figure 3 , Figure 4 and understanding the marked parameters, the method includes the following steps:

[0042] (1) Determine the layout characteristics of the drainage channel on the slope cross-section, including the number n, the length L1 of the non-permeable foam concrete hollow beam, the inclination angle θ, the drilling position, and the spacing d of the longitudinal drainage channels on the slope;

[0043] In step (1), first, according to the local climate statistical data results, determine the maximum 24-hour rainfall h max at the location of the slope. For example, h max = 23.6 mm. Then, determine the number n of the drainage channels on the slope cross-section by the following formula:

[0044]

[0045] From the maximum 24-hour rainfall h max = 23.6 mm, the number of the drainage channels on the slope cross-section can be initially determined to be 1;

[0046] Secondly, determine the drilling position at the toe of the slope according to actual experience or common sense, and determine the elevation of the drilling position from the bottom of the slope. For example, the elevation from the bottom of the slope is 0.1 m;

[0047] Next, determine the inclination angle θ of each drainage channel where the borehole is located at the toe of the slope and the length L1 of the non-permeable foamed concrete hollow beam of each drainage channel. Among them, L1 makes the end of the non-permeable foamed concrete hollow beam located at a higher water head in the seepage field, and on the premise that the intersection of the equipotential line and the phreatic line where the end of the hollow beam is located is at a height h≥1m from the bottom of the slope, θ makes the distance between the borehole of the non-permeable concrete pile and the phreatic line the shortest.

[0048] In practical applications, a drainage channel can be roughly determined first, and it is checked whether the conditions of h≥1m and the shortest distance between the borehole and the phreatic line are satisfied at the same time. If not, the inclination angle θ and the length L1 of the hollow beam are readjusted.

[0049] Specifically, select point A at a height of 0.1m from the bottom of the slope on the slope surface as the drill hole. According to experience, 0°<θ≤10°, and initially select θ = 5.0° in this drill hole.

[0050] Determine the length L1 of the non-permeable foamed concrete hollow beam of the drainage channel. L1 makes the end of the non-permeable foamed concrete hollow beam located at a higher water head in the seepage field, and the bottom water head h sl2 , h sl2 -h sl1 ≥0.2m. Extend AB. In this drill hole, when the hole depth is 13m, the bottom pressure water head is 2.23m, then the water head difference between the bottom and the orifice satisfies h sl2 -h sl1 ≥0.2m.

[0051] Finally, determine the longitudinal drainage channel distance d = 4m of the slope according to the longitudinal length of the slope and the number n of drainage channels.

[0052] (2) Determine the inner diameter r of the cross-section of the non-permeable foamed concrete hollow beam according to the rainfall characteristics of the location where the slope is located ( Figure 1 as shown), and determine the outer diameter R1 of the non-permeable foamed concrete hollow beam according to the strength of the non-permeable foamed concrete ( Figure 1 as shown)

[0053] In step (2), determine the cross-sectional characteristics of the non-permeable foamed concrete hollow beam, including the inner diameter r and the outer diameter R1. The specific implementation steps are as follows:

[0054] Determine the inner diameter r of the non-permeable foamed concrete hollow beam. r is determined by the following formula:

[0055]

[0056] According to the maximum 24-hour rainfall h max = 23.6mm, the inner diameter r of the non-permeable foamed concrete hollow beam is 50mm;

[0057] Determine the outer diameter R1 of the non-permeable foam concrete hollow beam, and R1 is determined by the following formula:

[0058]

[0059] That is, R1 = 3×50 = 150 mm.

[0060] (3) Determine the length L2 and diameter R2 of the permeable foam concrete beam according to the requirement of discharging free water in the slope ( Figure 1 as shown)

[0061] In step (3), determining the length L2 and diameter R2 of the permeable foam concrete beam includes the following steps:

[0062] The length of the permeable foam concrete beam ② is L2:

[0063] L2 = L1 + 0.2 = 13 + 0.2 = 13.2 m

[0064] The diameter R2 of the permeable foam concrete beam is equal to the inner diameter r of the non-permeable foam concrete hollow beam, that is, R2 = 50 mm.

[0065] (4) According to the described layout characteristics and the outer diameter R2 of the non-permeable foam concrete hollow beam, carry out inclined jet grouting construction on the slope of the non-permeable foam concrete hollow beam by using the jet grouting pile construction method

[0066] In step (4), the construction operation of the non-permeable foam concrete hollow beam includes the following specific steps:

[0067] (4-1) Prepare non-permeable foam concrete (for example, 1 m 3 )

[0068] Mix 400 kg of cement and 230 kg of water and stir to obtain a slurry;

[0069] Add 650 L of foaming liquid with a mass ratio of 1:40 (mass of foaming agent to mass of water) to the slurry, and stir slowly and fully to obtain non-permeable foam concrete;

[0070] (4-2) Using the jet grouting pile construction method, jet grout the non-permeable foam concrete obliquely according to the determined parameters, where the parameters include the drilling position, inclination angle θ, length L1, inner diameter r, outer diameter R1, and jet grouting pile length L1.

[0071] (5) After the non-permeable foam concrete starts to set, drill holes along the axis of the non-permeable foam concrete jet grouting pile according to the inner diameter r in step (3) to obtain a non-permeable foam concrete hollow beam, and fill the hollow beam with permeable foam concrete with a permeability coefficient K and a length L2

[0072] In step (5), the construction operation of the permeable foam concrete includes the following steps:

[0073] (5-1) Drill a hole along the axis of the non-permeable foam concrete jet grouting pile according to the inner diameter r to obtain a non-permeable foam concrete hollow beam;

[0074] (5-2) Prepare permeable foam concrete (for example, 1m 3 ):

[0075] Mix 446 kg of cement, 125 kg of water, and 179 kg of sand to form a slurry;

[0076] Add 650 L of foaming liquid with a mass ratio of foaming agent to water of 1:40 to the slurry, and stir evenly slowly and sufficiently to obtain permeable foam concrete with a permeability coefficient K;

[0077] (5-3) Pour the prepared permeable foam concrete into the drilled hole, with the pouring length of L2, and vibrate it to ensure that the drilled hole is completely filled.

[0078] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for strengthening a slope through a drainage channel, characterized in that, The drainage channel is composed of a non-permeable foam concrete hollow beam and permeable foam concrete filling the inside of the hollow beam, and the drainage channel is arranged in the slope from the slope inclined plane; the method includes the following steps: (1) Determine the layout characteristics of the drainage channel on the cross-section of the slope, including the number n, the length L1 of the non-permeable foam concrete hollow beam, the inclination angle θ, the drilling position, and the spacing d of the longitudinal drainage channels on the slope; (2) Determine the inner diameter r of the cross-section of the non-permeable foam concrete hollow beam according to the rainfall characteristics of the location where the slope is located, and determine the outer diameter R1 of the non-permeable foam concrete hollow beam according to the strength of the non-permeable foam concrete; (3) Determine the length L2 and diameter R2 of the permeable foam concrete beam according to the requirement of discharging free water in the slope, where the diameter R2 is equal to the inner diameter r; (4) According to the layout characteristics and the outer diameter R1 of the non-permeable foam concrete hollow beam, perform inclined jet grouting construction on the slope of the non-permeable foam concrete hollow beam by using the jet grouting pile construction method; (5) After the non-permeable foam concrete begins to set, drill holes along the axis on the non-permeable foam concrete jet grouting pile according to the inner diameter r in step (3) to obtain a non-permeable foam concrete hollow beam, and fill the hollow beam with permeable foam concrete with a permeability coefficient K and a length L2.

2. The method according to claim 1, wherein In step (1), the determination of the layout characteristics of the drainage channel includes the following steps: (1-1) Determine the maximum 24-hour rainfall h at the location of the slope max , and determine the number n of drainage channels on the cross-section of the slope by the following formula: Among them, h1 and h3 respectively represent the 24-hour rainfall limit values; (1-2) Determine the drilling position at the toe of the slope and its elevation from the bottom of the slope; (1-3) Determine the inclination angle θ of each drainage channel where the drill hole is located at the toe of the slope and the length L1 of the non-permeable foam concrete hollow beam of each drainage channel. Among them, L1 makes the end of the non-permeable foam concrete hollow beam located at a place with a higher water head in the seepage field, and on the premise of satisfying that the elevation h of the intersection point of the equipotential line and the phreatic line where the end of the hollow beam is located from the bottom of the slope is ≥1m, θ makes the distance between the non-permeable concrete pile drill hole and the phreatic line the shortest; (1-4) Determine the distance d of the longitudinal drainage channels on the slope.

3. The method according to claim 2, characterized in that In step (2), the inner diameter r of the cross-section is determined by the following formula: The outer diameter R1 is determined by the following formula: Among them, α and β are constant coefficients, and the outer diameter is determined according to the inner diameter of the cross-section.

4. The method according to claim 3, wherein In step (3), the length L2 = L1 + 0.2m; Select the ground as the reference plane, and the seepage water head at the end of the non-permeable foam concrete pile is: where z is the position head / m, P is the groundwater pressure / kPa, and γ w is the unit weight of water / kN / m 3 ; The head h at the top of the impermeable foam concrete sl2 = 0.1 m.

5. The method according to claim 1, characterized in that In step (5), the preparation process of the permeable foam concrete with the permeability coefficient K includes the following steps: Mix 446 kg of cement, 125 kg of water, and 179 kg of sand to form a slurry; Mix the foaming agent and water in a mass ratio of 1:40 to obtain a foaming liquid, add 650 L of the foaming liquid to the slurry, and fully and slowly stir evenly to obtain permeable foam concrete with a permeability coefficient K.

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