Method for judging safety of grouting inclined nail type sealing of ground water gushing hole

Abstract

This invention relates to a method for determining the safety of grouting-type inclined nail sealing of ground water seepage holes. Currently, there is a lack of accurate methods for determining the safety of grouting-type inclined nail sealing of ground water seepage holes. This method obtains the cross-sectional area of ​​the water seepage hole and determines its equivalent diameter; obtains the undrained shear strength of the soil surrounding the water seepage hole; determines the effective sealing length based on the sealing volume of the sealing material; calculates the sealing force provided by the grout; calculates the sealing force provided by the inclined nail; uses a flow meter to obtain the flow velocity of water emerging from the water seepage hole and calculates the water seepage thrust; compares the total jacking force and the total sealing force to determine whether the seal is safe. This method comprehensively considers the sealing force provided by the sealing material and the inclined nail, as well as the jacking force of the grout and the water seepage thrust, thereby determining whether the seal is safe. The method is reasonable, and the results are accurate and objective, providing support for the safe operation of concrete water conveyance tunnels.

Description

Technical Field

[0001] This invention relates to the field of concrete water conveyance tunnel engineering technology, specifically to a method for determining the safety of grouting inclined nail sealing of ground water seepage holes. Background Technology

[0002] Concrete water conveyance tunnels are a common type of hydraulic engineering structure. In reservoir connection sections, concrete water conveyance tunnels often operate under pressure. During construction, factors such as the heat of hydration of the concrete and deformation of the surrounding rock can cause cracks in the concrete. Under pressure, water inside the tunnel can diffuse along these cracks into the surrounding soil and rock. If there are weak or fractured zones in the surrounding soil and rock, water may gush out to the surface along these zones, forming water seepage points. To address this, sealing the opening and reinforcing it with 45° inclined nails followed by grouting is a common method. However, the safety of the sealing is largely judged based on engineering experience, and there are currently no theoretical methods to guide this process.

[0003] In view of this, it is necessary to propose a method for determining the safety of the grouting oblique nail sealing of the ground water seepage hole to ensure the sealing safety of the concrete water conveyance tunnel during operation. Summary of the Invention

[0004] The purpose of this invention is to provide a method for determining the safety of grouting oblique nail sealing of ground water seepage holes, so as to solve the problem that it is currently impossible to accurately determine whether grouting oblique nail sealing of ground water seepage holes is safe.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] A method for determining the safety of grouting oblique nail-type sealing of ground water seepage holes, the method comprising:

[0007] The cross-sectional area of ​​the water vent is obtained using a laser rangefinder, and the equivalent diameter of the water vent is determined.

[0008] The undrained shear strength of the soil surrounding the water bubble was obtained using a miniature vane shear apparatus.

[0009] Determine the effective sealing length based on the sealing volume of the sealing material;

[0010] Calculate the sealing force provided by the grouting body;

[0011] Determine the number, diameter, and length of the angled nails to be driven in, and calculate the sealing force provided by the angled nails;

[0012] The velocity of the water gushing from the vent is obtained using a flow meter, and the thrust of the vent is calculated.

[0013] The total jacking force is obtained from the jacking force of the grout and the jacking force of the water seepage. The total sealing force is obtained from the sealing force provided by the grout and the sealing force provided by the inclined nail. The sealing force is then compared to determine whether the seal is safe.

[0014] Furthermore, the cross-sectional area of ​​the water vent is obtained using a laser rangefinder, and the equivalent diameter of the water vent is determined, including:

[0015] Set the laser rangefinder in front of the water outlet and mount it on top of a stable tripod.

[0016] Using the area measurement function of a laser rangefinder, the internal area A around the cross-section of the water vent is measured, which is the cross-sectional area of ​​the water vent.

[0017] Calculate the equivalent diameter D of the water inlet:

[0018]

[0019] Furthermore, the undrained shear strength of the soil surrounding the water-rising hole was obtained using a miniature vane shear apparatus, including:

[0020] The undrained shear strength c of the soil surrounding the water bubble was measured in situ using a miniature vane shear apparatus. u .

[0021] Furthermore, based on the sealing volume of the sealing material, the effective sealing length is determined, including:

[0022] The sealing volume V of the sealing material is measured using a graduated cylinder.

[0023] Calculate the effective sealing length L0 of the sealing material:

[0024]

[0025] in:

[0026] α is the reduction factor for the sealing length.

[0027] Further, the sealing force provided by the grouting body is calculated, including:

[0028] The sealing force R1 provided by the grouting body is:

[0029] R1=βπDL0c u ;

[0030] in:

[0031] β is the soil strength enhancement coefficient.

[0032] Further, determine the number, diameter, and length of the angled nails to be driven in, and calculate the sealing force provided by the angled nails, including:

[0033] Determine the number \(n\), diameter \(d\), and length \(L1\) of the inclined nails driven in;

[0034] The plugging force \(R2\) provided by the inclined nails:

[0035]

[0036] Further, use a flow velocity meter to obtain the flow velocity of the water gushing out from the water gushing hole, and deduce the water gushing thrust, including:

[0037] Use a flow velocity meter to measure the flow velocity \(v\) of the water gushing out at the orifice of the water gushing hole;

[0038] Calculate the water gushing thrust \(T1\) of the water gushing out of the water gushing hole:

[0039]

[0040] Where:

[0041] \(\rho\) w Is the density of water.

[0042] Further, obtain the total jacking force based on the jacking force of the grouting body and the water gushing thrust, and obtain the total plugging force based on the plugging force provided by the grouting body and the plugging force provided by the inclined nails, and judge whether the seal is safe after comparison, including:

[0043] Calculate the jacking force \(T2\) of the grouting body:

[0044] \(T2 = Ap\); <^

[0045] Where:

[0046] \(p\) is the grouting pressure;

[0047] Based on the jacking force \(T2\) of the grouting body and the water gushing thrust, obtain the total jacking force \(T1\), and calculate the total jacking force \(T\):

[0048] \(T = T1 + T2\);

[0049] Based on the plugging force \(R1\) provided by the grouting body and the plugging force \(R2\) provided by the inclined nails, obtain the total plugging force \(R\):

[0050] \(R = R1 + R2\);

[0051] Judge whether the seal is safe:

[0052] If \(R\geq T\), the seal is safe;

[0053] If \(R < T\), it is not safe.

[0054] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0055] The safety assessment method provided in this paper is used for the reinforcement safety monitoring of concrete water conveyance tunnels. It comprehensively considers the sealing force from the sealing material and the sealing force from the inclined nails, as well as the jacking force and water seepage thrust provided by the grouting body. It compares and judges whether the seal is safe. The method is reasonable and the results are accurate and objective, providing support for the safe operation of concrete water conveyance tunnels. Attached Figure Description

[0056] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other embodiments can be obtained from these drawings without creative effort.

[0057] Figure 1 This is a flowchart of the method of the present invention. Detailed Implementation

[0058] To facilitate understanding of the present invention, a more complete description will be given below with reference to the accompanying drawings. Preferred embodiments of the invention are shown in the drawings. However, the invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of the invention.

[0059] In the description of this invention, it should be understood that all technical and scientific terms used have the same meaning as commonly understood by one of ordinary skill in the art. In case of conflict, the definitions in this specification shall prevail. Unless otherwise specified, the technical means used in the embodiments are conventional means well known to those skilled in the art, and the devices used in the embodiments are existing devices. The limitation of the means or devices should not be construed as a limitation of the present invention, and means or devices of the same type for solving the same technical problem are all within the protection scope of the present invention.

[0060] In the description of this invention, it should be understood that the method involves multiple steps and should not be construed as a limitation on the order of the steps. Technical solutions obtained by changing the order of steps when solving the same technical problem are also within the protection scope of this invention.

[0061] This invention provides a method for determining the safety of grouting oblique nail sealing of ground water seepage holes, based on the following...

[0062] Working principle:

[0063] When using a slanted nail seal to plug a water vent, the sealing material provides the sealing force on one hand, and the slanted nail provides the sealing force on the other hand. The grout pressure and the water vent pressure provide the pushing force of the sealing material. If the latter is greater than the sum of the former two, the sealing material will push the seal out under the action of the grout pressure, causing the seal to break.

[0064] like Figure 1 The method of the present invention includes the following steps:

[0065] S1: Obtain the cross-sectional area of ​​the water bubble using a laser rangefinder and determine its equivalent diameter, including:

[0066] S101: Set the laser rangefinder in front of the water outlet and mount it on top of a stable tripod;

[0067] S102: Using the area measurement function of the laser rangefinder, measure the internal area A around the cross-section of the water vent, which is the cross-sectional area of ​​the water vent.

[0068] S103: Calculate the equivalent diameter D of the water inlet:

[0069]

[0070] S2: Obtaining the undrained shear strength of the soil surrounding the water-bearing hole using a miniature vane shear apparatus, including:

[0071] The undrained shear strength c of the soil surrounding the water bubble was measured in situ using a miniature vane shear apparatus. u .

[0072] S3: Determine the effective sealing length based on the sealing volume of the sealing material, including:

[0073] S301: Measure the sealing volume V of the sealing material using a graduated cylinder;

[0074] S302: Calculate the effective sealing length L0 of the sealing material:

[0075]

[0076] in:

[0077] α is the reduction factor for the blocking length, which can be taken as 0.75.

[0078] S4: Calculate the sealing force provided by the grouting body, including:

[0079] The sealing force R1 provided by the grouting body is:

[0080] R1=βπDL0c u ;

[0081] in:

[0082] β is the soil strength enhancement coefficient, which can be taken as 1.10.

[0083] S5: Determine the number, diameter, and length of the angled nails to be driven in, and calculate the sealing force provided by the angled nails, including:

[0084] S501: Based on the construction plan, determine the number n, diameter d, and length L1 of the angled nails to be driven in;

[0085] S502: The sealing force R2 provided by the angled nail:

[0086]

[0087] S6: Use a flow meter to obtain the flow velocity of the water emerging from the vent, and calculate the thrust of the water flow, including:

[0088] S601: Use a flow meter to measure the flow velocity v of the gushing water at the opening of the gushing hole;

[0089] S602: Calculate the thrust T1 of water escaping from the vent:

[0090]

[0091] in:

[0092] ρ w The density of water is taken as 1000 kg / m³. 3 .

[0093] S7: The total jacking force is obtained based on the jacking force of the grouting body and the water seepage force. The total sealing force is obtained based on the sealing force provided by the grouting body and the sealing force provided by the inclined nails. After comparison, it is determined whether the seal is safe, including:

[0094] S701: Calculate the jacking force T2 of the grouting body:

[0095] T2 = Ap;

[0096] in:

[0097] p represents the grouting pressure, which is determined by the construction plan.

[0098] S702: Based on the jacking force T2 of the grouting body and the water seepage thrust, obtain the total jacking force T1, and calculate the total jacking force T:

[0099] T = T1 + T2;

[0100] S703: The total sealing force R is obtained based on the sealing force R1 provided by the grouting body and the sealing force R2 provided by the inclined nail.

[0101] R = R1 + R2;

[0102] S704: Determine whether the seal is safe:

[0103] If R ≥ T, the seal is safe;

[0104] If R < T, it is not safe.

[0105] Example:

[0106] In a water conveyance tunnel in our country, due to severe disturbance of the surrounding rock and soil mass during construction, after the tunnel was completed, water gushing holes appeared on the ground. The high-pressure grouting scheme was adopted to seal them using sealing materials (such as cement mortar, fine-grained concrete, etc.). In order to determine whether the seal is safe, the method of the present invention was used for determination.

[0107] A laser rangefinder was set in front of the water gushing hole and installed on the top of a stable tripod. Using the area measurement function of the laser rangefinder, the internal area A of the perimeter of the cross-section of the water gushing hole was measured to be 0.07 m 2 . Further, the equivalent diameter D of the water gushing hole was determined to be 0.30 m. Using a miniature vane shear tester, the undrained shear strength c of the soil around the water gushing hole was in-situ tested u to be 41 kPa. The sealing material was put into a measuring cylinder, and its volume V was measured to be 0.2 m 3 , and the effective sealing length L0 of the sealing material for the water gushing hole was determined to be 2.14 m. The blocking force R1 provided by the grouting body was determined to be 90.64 kN. According to the construction plan, the number n of inclined nails driven in was determined to be 4, the diameter d of the inclined nails was 0.05 m, and the length L1 of the inclined nails was 0.5 m. The blocking force R2 provided by the inclined nails was determined to be 8.19 kN. Using a flowmeter at the mouth of the water gushing hole, the flow velocity v of the gushing water was measured to be 2.2 m / s. The water gushing thrust T1 of the water gushing hole was determined to be 0.17 kN. The grouting pressure p was determined to be 1000 kPa according to the construction plan, and the top thrust T2 of the grouting body was determined to be 70 kN. The total blocking force R was determined to be 98.83 kN, and the total top thrust T was determined to be 70.17 kN. Since R > T, it was determined that the seal is safe.

[0108] The above uses specific examples to elaborate on the present invention, which is only used to help understand the present invention and is not intended to limit the present invention. For those skilled in the technical field to which the present invention pertains, based on the idea of the present invention, several simple deductions, deformations or substitutions can also be made.

Claims

1. A method for determining the safety of grouting and oblique nail sealing of ground water seepage holes, characterized in that: The method includes: The cross-sectional area of ​​the water vent is obtained using a laser rangefinder, and the equivalent diameter of the water vent is determined. The undrained shear strength of the soil surrounding the water bubble was obtained using a miniature vane shear apparatus. Determine the effective sealing length based on the sealing volume of the sealing material; Calculate the sealing force provided by the grouting body, including: The sealing force provided by the grouting body Is: ； in: Ks is the strength enhancement coefficient of soil; Equivalent diameter of the water hole; effective sealing length of the sealing material; C is the undrained shear strength of the soil around the hole; Determine the number, diameter, and length of the angled nails to be driven in, and calculate the sealing force provided by the angled nails, including: Determine the number of angled nails to be driven in. ,diameter ,length ; The sealing force provided by the angled nail : ； The velocity of the water gushing from the vent is obtained using a flow meter, and the thrust of the vent is calculated, including: The velocity of the water gushing out is measured at the opening of the vent using a flow meter. ; Calculate the thrust of water escaping from the vent. : ； in: D is the density of water; The internal area of ​​the perimeter of the cross-section of the water outlet; The total jacking force is obtained based on the jacking force of the grouting body and the water seepage force. The total sealing force is obtained based on the sealing force provided by the grouting body and the sealing force provided by the inclined nails. After comparison, the safety of the seal is determined, including: Calculating the thrust of a grout body : ； in: P is the grouting pressure; Based on the jacking force of the grouting body The total top thrust is obtained by combining the thrust from the water flow. Calculate the total thrust. : ； Based on the sealing force provided by the grouting body The sealing force provided by the angled nail To obtain the total blocking force : ； Determining if the seal is secure: If then the seal is safe. If then unsafe.

2. The method according to claim 1, characterized in that: The cross-sectional area of ​​the water seepage hole is obtained using a laser rangefinder, and the equivalent diameter of the water seepage hole is determined, including: Set the laser rangefinder in front of the water outlet and mount it on top of a stable tripod. Using the area measurement function of a laser rangefinder, the internal area of ​​the perimeter of the cross-section of the water vent was measured. That is, the cross-sectional area of ​​the water outlet; Calculate the equivalent diameter of the water vent. : 。 3. The method according to claim 2, characterized in that: The undrained shear strength of the soil surrounding the water bubble was obtained using a miniature vane shear apparatus, including: The undrained shear strength of soil around the water outlet is tested in situ by using a miniature vane shear apparatus .

4. The method according to claim 3, characterized in that: The effective sealing length is determined based on the volume of the sealing material to be sealed, including: Measuring the volume of the sealing material with a measuring cylinder ; Calculate the effective sealing length of the sealing material : ； in: is the length reduction factor for plugging.

Images