Slope soil body permeability coefficient monitoring method and system

Abstract

To provide a slope soil body permeability coefficient monitoring method.SOLUTION: A slope soil body permeability coefficient monitoring method comprises the following steps of: guiding underground water at a measurement point above the ground for natural drainage; measuring water flow movement characteristics of a drainage port; and inversely measuring and calculating a slope groundwater elevation and a slope groundwater permeability coefficient by utilizing a flow velocity and flow change data of the drainage port in a measurement interval and combining a groundwater dynamic viscosity and characteristic parameters of a water guide pipe structure material. According to the optimization scheme, technical contradiction between undisturbed flow velocity measurement and enhancement of water level elevation difference is considered by arranging a measuring pipe and an assisting discharge pipe, and local and overall precision and sensitivity of the measurement scheme are improved. The invention also solves the problem of measuring and calculating the hydrodynamic viscosity of the underground water by using ground environment temperature. The invention also provides a monitoring system scheme. The method is a brand-new underground water permeability coefficient monitoring technical scheme, and is low in cost and low in energy consumption.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to slope monitoring measurement technology, and in particular to a method and system for monitoring the infiltration characteristics of slope soil bodies, belonging to the fields of environmental monitoring measurement technology and construction geology soil body monitoring measurement technology.

Background Art

[0002] The soil body infiltration coefficient is an important geological parameter of slopes. In various slope safety stability analyses, slope disaster prevention and control studies, and slope disaster monitoring early warning technologies, the slope soil body infiltration coefficient is almost an indispensable soil body characteristic parameter and is the basis for the micro-level force balance analysis of slope soil bodies.

[0003] Conventional soil body infiltration coefficient measurement technologies generally have two solutions. The first solution is to adopt the combination of on-site soil body sampling and laboratory instrument analysis. Such a solution generally designs and develops various experimental measurement devices and instruments, and then designs special instruments for different soil types, and collects relevant data with precise sensors. The advantage of such a solution is that the controllability of measurement accuracy is good and the accuracy of measurement results is relatively high. The obvious defects are mainly that the process is relatively complicated and the time is relatively long. Moreover, the more prominent defect is that the instrument measurement environment belongs to a closed and ideal environment, the change of environmental conditions in instrument simulation is limited, the force received by the test original soil is relatively stable and uniform, and there is always a certain difference between the test environment and the field real environment.

[0004] The second type of solution is in-situ measurement of soil. The prominent advantage in the technical design of such a solution lies in the field authenticity of the measurement environment, which can precisely overcome the defects of the first type of solution. However, the technical defects of the conventional in-situ measurement solutions are equally obvious. The conventional technology ZL 201810501818.X discloses a device and a test method for measuring the in-situ infiltration coefficient of soil. The measuring device includes a pressure device, a pressure controller, a water flow velocity meter, a measuring rod, a pressure sensor, a vertical meter, a water tank, and a strainer. The pressure controller is electrically connected to the pressure device, the water flow velocity meter, and the pressure sensor. The pressure controller integrates the display, measurement, and control of pressure. The pressure device of the product can provide the intensity of negative pressure to the measured soil body by a vacuum pump or a pressure pump under the action of the pressure controller, and can also provide the intensity of positive pressure, and is applicable to soil and clay. The main technical defects of this technology are as follows: First, in the measurement process, it is necessary to construct a specific measurement platform. The pressure pump always provides the intensity of positive pressure in the measurement process, and various data are read under this condition. That is to say, although the measurement is carried out "in-situ", the measured soil body is actually a local soil body under artificially controlled conditions all the time. The measurement process is "in-situ" but "unnatural", and the most important technical value of in-situ measurement is lost. Second, the conventional pumping water volume is relatively large, and it is necessary to separately add power conditions, which requires additional energy loss. At the same time, there are many measurement parameters in this process, the monitoring process is relatively complex, and measurement errors are likely to occur.

Summary of the Invention

Problems to be Solved by the Invention

[0005] An object of the present invention is to provide a technology for measuring the infiltration coefficient of slope soil that can realize the technical value of in-situ and natural measurement in the field in view of the deficiencies of the prior art.

Means for Solving the Problems

[0006] To achieve the above object, the present invention first provides a method for monitoring the permeability coefficient of a slope soil body, and its technical solution is as follows.

[0007] A method for monitoring the permeability coefficient of a slope soil body, comprising determining an underground measurement site P and a measurement interval In the formula JPEG2025110851000002.jpg75170JPEG2025110851000003.jpg10170, k is the soil body permeability coefficient of the underground measurement site, in m / s, JPEG2025110851000004.jpg59170b is the length of the boring hole, in m, and is determined by the measurement design operation parameters.

[0008] The above method for monitoring the permeability coefficient of a slope soil body is based on the principle of liquid flow energy balance of a communicating pipe, guiding groundwater to the ground, and inverse calculating the soil body permeability coefficient of the underground monitoring site by monitoring the water flow movement parameter data of the ground drainage outlet. Based on previous research, the data basis of the inverse calculation model includes boring hole data and groundwater change parameters at the measurement time. One is the water flow movement monitoring data (flow rate W) of the ground drainage outlet JPEG2025110851000005.jpg5170It can be measured by using conventional technologies (for example, CN 2023114987624, a method for measuring the elevation of the groundwater level, a water storage measurement system and applications).

[0009] Based on previous research data, the present invention optimizes the above monitoring method. Specifically, based on Darcy's law, an inverse calculation model for monitoring the relationship between the flow velocity at the drainage outlet and the soil body permeability coefficient parameters at the measurement site is directly constructed, and the kinematic viscosity of groundwater is incorporated into the inverse calculation model to ensure that the influence of the fluid properties of groundwater on the drainage outlet flow velocity can be embodied in the measurement of the calculation model. The groundwater elevation a at time t at point P is calculated by Equation 2.

[0010] In the 11170 type, a - the groundwater level (m) at point P at time t, v - the flow velocity (m / s) of the surface drainage outlet at time t, μ - the kinematic viscosity of groundwater (Pa·s), L - the length (m) of the aqueduct, ρ - the groundwater density JPEG2025110851000007.jpg17170

[0011] In the above optimization scheme, the kinematic viscosity μ of groundwater can be determined by using conventional techniques, such as experimental measurements or direct viewing of an empirical manual. In order to establish a technical solution with consistent technical logic, a further optimization of the present invention is to solve the technical problem of monitoring the flow velocity using the drainage outlet and calculating the kinematic viscosity μ of groundwater. The kinematic viscosity μ of the groundwater fluid is calculated by the simultaneous equations of Equation 3.

[0012] JPEG2025110851000008.jpg7170JPEG2025110851000009.jpg12170 In the formula, f - the kinematic viscosity of groundwater (m 2 / s), e - the surface environmental temperature (°C).

[0013] The optimization scheme of the above slope soil permeability coefficient monitoring method further includes the optimization of the following monitoring operation conditions in addition to the optimization of the aforementioned inverse calculation. It does not require that the following optimizations must be carried out simultaneously.

[0014] Optimization 1: Within the measurement interval T, the surface drainage outlet of the measuring device maintains stable drainage, and T is 8h to 24h.

[0015] Optimization 2: After installing the water conduit, perform an auxiliary water filling operation at the drainage outlet end to fill the water conduit line and guide the drainage at the drainage outlet. In slope groundwater monitoring, generally, utilize the exposed rock surface of the slope body to make the drainage outlet of the water conduit lower than the water intake and form a certain elevation difference. Therefore, after guiding the drainage outlet to start drainage, the drainage process can be carried out spontaneously and stably without the need for any additional energy consumption for lifting and filling water. The auxiliary water filling operation may be to exhaust air at the drainage outlet end to create a negative pressure, or to inject water into the pipeline from the drainage outlet, etc.

[0016] Optimization 3: Insert N water conduits into the permeable cylinder, where N≥2. The water intakes of the N water conduits are at the same point below the liquid level in the permeable cylinder, and the drainage outlets are at the same elevation on the ground. One of the N water conduits is a measuring pipe, and the rest are auxiliary drainage pipes. Measure the monitoring data D of the groundwater characteristics at the collection point P from the drainage outlet of the measuring pipe. This optimization, on the one hand, completes the measurement of the groundwater elevation a by collecting the instantaneous drainage flow rate based on the ultra-fine drainage outlet at time t JPEG2025110851000010.jpg5170 By clearly capturing the change characteristics of the groundwater more easily, the sensitivity and accuracy of the monitoring plan are enhanced from two aspects. The specifications of the N water conduits are the same. For different types of slope soil bodies, a more improved design of the number of water conduits is that when the slope soil body is clay, N = 3 - 7; when the slope soil body is silt loam, N = 7 - 13; when the slope soil body is sandy soil, N = 16 - 24.

[0017] Optimization 4: The boring hole and the permeable cylinder are installed perpendicular to the slope face.

[0018] Optimization 5: Hold the conical permeable stone at the end of the permeable cylinder core layer sleeve in the underground single aquifer, and the inner diameter of the water conduit is less than 5 mm.

[0019] Based on the above slope soil body permeability coefficient monitoring method of the present invention, the present invention simultaneously provides a groundwater storage capacity monitoring measurement system, and the technical solution is as follows.

[0020] A slope soil body permeability coefficient monitoring system, which sets a slope soil body permeability coefficient measurement site P, drills a boring hole at point P and inserts a water permeable cylinder to ensure that groundwater enters the water permeable cylinder, extends the water intake of the water conduit below the liquid level in the water permeable cylinder, leads the drainage outlet of the water conduit to the ground, and when the drainage at the drainage outlet becomes stable, measures the monitoring data D of the groundwater characteristics at the collection point P, and calculates the soil body permeability coefficient k at point P by using the monitoring data D and the measurement design operation parameters.

Effect of the Invention

[0021] Compared with the prior art, the beneficial effects of the present invention are as follows. (1) According to the prior research of the present invention, a water flow pipeline is constructed between the underground boring hole measurement position and the ground monitoring position by using a water conduit. Based on the principle of liquid flow energy balance, it is discovered that the flow velocity of the ground drainage outlet of the pipeline can characterize the elevation characteristics of the groundwater level in the boring hole. The technical solution of the present invention expands this research discovery. By introducing the measurement time parameters characterized in the measurement interval, the groundwater elevation data at the specified time (i.e., both ends of the measurement interval) is calculated. The drainage outlet flow rate parameter is introduced into the groundwater infiltration characteristic inverse calculation model, and by utilizing the exposed rock surface characteristics of the slope terrain, it is realized that there is no extra energy consumption in the measurement process. Thereby, the present invention provides a technical solution for monitoring the groundwater infiltration coefficient completely at the original position of the measurement site and under sufficient natural environmental conditions. It accurately overcomes the technical defect of the conventional in-situ monitoring technology, which is "in-situ but not natural", and is a completely new technical concept for monitoring the groundwater infiltration coefficient. (2) The present invention further combines with the Darcy's law of groundwater infiltration flow in the soil body, and incorporates the kinematic viscosity of groundwater and the aqueduct structure / material characteristic parameters into the groundwater elevation calculation model defined by the drainage outlet flow velocity, thereby overall enhancing the accuracy of inversely calculating the groundwater elevation calculation model using the drainage outlet flow velocity, and also enhancing the accuracy of the groundwater infiltration coefficient monitoring technology of the present invention. (3) In the technical concept of the present invention, when adopting the communicating pipe principle drainage measurement method and inversely calculating and measuring the groundwater elevation characteristics of the underground part by using the ground drainage outlet flow velocity, a preferred solution is to use an ultra-fine water conduit in combination with a high-precision micro liquid flow velocity and flow rate meter to complete the detection of the drainage outlet flow velocity instantaneously, and ensure that only extremely tiny disturbances that can be ignored occur with respect to the elevation of the groundwater level. In the overall solution for monitoring the groundwater infiltration coefficient, the ideal state is that there is a clear elevation difference as large as possible between the groundwater elevations at two specified times, thereby amplifying the groundwater infiltration characteristics to make it easier to capture and monitor. In order to accurately solve this contradiction, the present invention improves the design of the water conduit, installs multiple water conduits, and distinguishes between the measurement pipe and the auxiliary drainage pipe.In this way, the measurement pipe can improve the flow velocity collection accuracy by diverting the design of the thin electrode water conduit + micro flow velocity flow meter. The auxiliary drain pipe can realize the parallel drainage of multiple pipelines, accelerate the elevation change rate, and form a relatively obvious elevation difference as much as possible. Moreover, if all the water conduits are further limited to adopt the same specifications, the influence of the disturbance of the water surface in the permeable cylinder due to the inflow water siphon effect of the auxiliary drain pipe on the inflow water of the measurement pipe can be reduced. The optimization plan balances the local and overall accuracy and sensitivity of the monitoring plan, and enhances the technical value of the in-situ monitoring technology plan for the groundwater infiltration coefficient. (4) The equipment and implementation of the present invention both have the characteristics of low cost and low energy consumption, and are applicable to various slope disaster prevention and control plans in mountainous areas.

Brief Description of the Drawings

[0022]

Figure 1

Embodiments for Carrying out the Invention

[0023] Hereinafter, preferred embodiments of the present invention will be further described in conjunction with the drawings.

[0024] <Example 1> As shown in FIG. 1, the method of the present invention is used to monitor the infiltration coefficient of a certain slope soil body.

[0025] 1. Layout of the target slope body and monitoring instruments The slope to be monitored is located in Jiangshan City, Zhejiang Province. The overall geological structure of the landslide is simple. There is a wide rainfall infiltration and recharge area at the rear edge of the slope. Moreover, the permeability of the slope soil body is good, the annual change of the groundwater level is relatively large, and the slope body infiltration coefficient is closely related to the safety and stability of the slope body. The method of the present invention is used to monitor the infiltration coefficient of this slope soil body.

[0026] Conduct on-site investigations to obtain background data for the monitoring plan. The on-site investigations referred to in this technology include various geological investigations, reconnaissance, surveying and mapping, measurement operations, and conventional simulation experiments, test experiments, observation experiments, analysis experiments, and acquisition of disaster histories for the slope site where the project is located, as well as acquisition of relevant technical specifications and empirical methods and data with reference functions.

[0027] It is a schematic layout diagram of the slope soil body permeability coefficient monitoring method.

[0028] To save words, only one set of monitoring intervals T in the monitoring plan will be described as a sample below. The implementation of the monitoring plan may be carried out as dynamic monitoring, that is, in continuous multi-monitoring intervals T.

[0029] Based on the background data of the monitoring plan, determine each measurement design operation parameter (Table 1). In the prior art, there are multiple specific methods for measuring the influence radius R. The embodiment for implementing the present invention adopts a method of determining R based on two parameters of unit drainage volume and unit water level drop, specifically as shown in Table 2.

[0030] Based on the background data, determine the underground measurement site P within the slope body, and determine the vertical projection site P' of point P on the slope normal plane. At this point, P' is perpendicular to the normal boring hole 4, the depth is below the groundwater level line, and the length of the boring hole 4 is b. Install a permeable cylinder 1 in the hole, Place the permeable cylinder 1 in the boring hole, ensure that the permeable cylinder 1 is perpendicular to the slope surface, extend the water conduit 2 into the permeable cylinder 1, and submerge the water intake 21 below the liquid level in the core layer sleeve 13. Pull out the drain outlet 22 of the water conduit 2 to the ground and connect a flow velocity measuring device. Hold the conical permeable stone 12 at the end of the core layer sleeve 11 of the permeable cylinder 1 in the underground single aquifer. For the detailed content of the installation of each component of the device, refer to the prior art (CN 2023114987624, Method for measuring the elevation of the groundwater level, water storage capacity measurement system and application). In this example, the flow velocity measuring device selects a high-precision micro liquid flow velocity and flow meter.

[0031] After installing the water conduit 2, perform an auxiliary water filling operation at the drain outlet 22 end. In this example, the auxiliary water filling operation is to give a certain initial pumping to the drain outlet 21 to guide the start of drainage.

[0032] 2. Monitoring data collection JPEG2025110851000011.jpg28170 Maintain stable drainage at the drain outlet within the measurement interval T.

[0033] Show the monitoring data in Table 1.

[0034] 3. Inverse calculation This embodiment specifically implements the optimization plan of the measurement method of the present invention, that is, all intermediate quantities are calculated and determined based on the hydrodynamic characteristics of the water flow at the drain outlet. Based on the measurement design operation parameters and the monitoring data D, calculate the kinematic viscosity f of the groundwater and the dynamic viscosity μ of the groundwater fluid in turn by the simultaneous equations of Equation 3. JPEG2025110851000012.jpg22170N The total flow rate of all the water conduits 2.

[0035] [Table 1] JPEG2025110851000013.jpg134148

[0036] [Table 2] JPEG2025110851000014.jpg47170

Explanation of symbols

[0037] 1 Water-permeable cylinder 2 Water conduit 21 Water intake 22 Drain outlet 3 Boring hole 4 Inclined plane 5 Initial groundwater level line

Claims

1. A method for monitoring the permeability coefficient of a sloped soil mass, comprising determining an underground measurement site P and a measurement interval In the formula, k is the permeability coefficient of the soil mass at the underground measurement site, in m / s, b is the length of the boring hole, in m, and is determined by the measurement design operation parameters. A method for monitoring the permeability coefficient of a sloped soil mass, characterized by the above.

2. The groundwater level a at point P at time t is calculated by Equation 2, In the formula, a is the groundwater level at t at point P, in m, v is the flow velocity of the surface drainage outlet at time t, in m / s, and is determined by the monitoring data D, μ is the kinematic viscosity of groundwater, in Pa·s, and is determined by the measurement design operation parameters, L is the length of the water conduit, in m, and is determined by the measurement design operation parameters, ρ - density of groundwater, g / cm ３ which is determined by measurement design operation parameters, c is the hydraulic radius of the water conduit, in m, and is determined by the measurement design operation parameters,

3. The kinematic viscosity μ of the groundwater fluid is calculated by the simultaneous equations of Equation 3, In the formula, f is the kinematic viscosity of groundwater, m ２ / s, and e is the ground environmental temperature, in °C, and is determined by the measurement design operation parameters. The monitoring method according to Claim 2, characterized by the above.

4. Within the measurement interval T, the surface drainage outlet of the measuring device maintains stable drainage, and T is 8 h to 24 h. The monitoring method according to any one of Claims 1 to 3, characterized by the above.

5. After installing the water conduit, perform an auxiliary water filling operation at the drainage outlet end to fill the water conduit line and guide the drainage of the drainage outlet. The monitoring method according to Claim 4, characterized by the above.

6. Insert N water conduits into the permeable cylinder, where N ≥ 2. The water intake ports of the N water conduits are at the same point below the liquid level in the permeable cylinder, and the drainage outlets are at the same elevation on the ground. One of the N water conduits is a measurement pipe, and the rest are auxiliary drainage pipes. Monitor the monitoring data D of the groundwater characteristics at the collection point P from the drainage outlet of the measurement pipe. The specifications of the N water conduits are the same. The monitoring method according to Claim 4, characterized by the above.

7. When the sloped soil mass is clay, N = 3 to 7; when the sloped soil mass is silt loam, N = 7 to 13; when the sloped soil mass is sand, N = 16 to 24. The monitoring method according to Claim 6, characterized by the above.

8. The boring hole and the permeable cylinder are installed perpendicular to the slope surface. The monitoring method according to Claim 4, characterized by the above.

9. The monitoring method according to claim 4, characterized in that a conical water-permeable stone at the end of the water-permeable cylinder core layer sleeve is held in a single underground aquifer, and the inner diameter of the water conduit is smaller than 5 mm.

10. A slope soil body permeability coefficient monitoring system realized by using the slope soil body permeability coefficient monitoring method according to any one of claims 1 to 3, comprising: setting a slope soil body permeability coefficient measurement site P, drilling a borehole at point P and inserting a water-permeable cylinder to ensure that groundwater enters the water-permeable cylinder, extending the water intake of the water conduit below the liquid level in the water-permeable cylinder, leading the water outlet of the water conduit to the ground, and when the drainage at the water outlet becomes stable, measuring the monitoring data D of the groundwater characteristics at the collection point P, and calculating the soil body permeability coefficient k at point P by using the monitoring data D and the measurement design operation parameters.

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