Improved Calculation Method for Siphon Drainage with Extended Horizontal Sections

Slope siphon drainage is a convenient and efficient above-ground drainage method that is free of manual power and can effectively maintain the stability of potential landslides and prevent the loss of life and property. The complex engineering topography inevitably requires the use of siphon drains with a total length of more than 150 m and a horizontal section length of more than 80 m, which significantly increases the difficulty of calculating the drainage capacity and thus affects the actual utilization of the project. The traditional siphon flow rate equation does not apply to long-pipe siphon conditions, especially when the lift is close to the limit, and there are significant errors in the calculation results, for which we propose a new calculation method. The proposed method considers both air release and flow-pattern classification. Thirty-six sets of experiments were conducted to validate our proposed calculation method. The results showed that our method not only calculated the siphon flow velocity well but also predicted the main flow pattern in the siphon in the experiment well. Furthermore, the equation for calculating the siphon flow velocity was extended to the siphon operation mode with long horizontal sections

Study on Siphon Drainage Capacity of Slopes with Long-Horizontal Pipe Sections

Siphon drainage, which is applicable in engineering as one of the effective methods to maintain slope stability, has many advantages, including no additional power requirements, simple construction, and low construction cost. However, due to topographic constraints and high farmland occupation costs, most projects inevitably use pipes with a total length of more than 100 m and horizontal sections of more than 50 m for drainage. The increase in pipe length has serious adverse effects on the siphon drainage process, limiting its drainage capacity and long-term applicability. Therefore, in slope siphon drainage, drainage efficiency and long-term effectiveness are critical factors in determining whether a particular pipe size can be used effectively for slope drainage management. This paper investigates the performance of different pipe diameters in drainage capacity, flow regime, and restarting ability under different head and pipe length combinations through theoretical analysis and extensive foot-scale model tests. It was found that a 5 mm pipe diameter, as a transitional pipe diameter between capillary and typical pipe diameter, has both capillary and gravity-dominated characteristics under different capillary and Reynolds number conditions, which can form a stable segmental plug flow while maintaining the presence of liquid film and preventing increased frictional losses along the course

Improved Calculation Method for Siphon Drainage with Extended Horizontal Sections

Slope siphon drainage is a convenient and efficient above-ground drainage method that is free of manual power and can effectively maintain the stability of potential landslides and prevent the loss of life and property. The complex engineering topography inevitably requires the use of siphon drains with a total length of more than 150 m and a horizontal section length of more than 80 m, which significantly increases the difficulty of calculating the drainage capacity and thus affects the actual utilization of the project. The traditional siphon flow rate equation does not apply to long-pipe siphon conditions, especially when the lift is close to the limit, and there are significant errors in the calculation results, for which we propose a new calculation method. The proposed method considers both air release and flow-pattern classification. Thirty-six sets of experiments were conducted to validate our proposed calculation method. The results showed that our method not only calculated the siphon flow velocity well but also predicted the main flow pattern in the siphon in the experiment well. Furthermore, the equation for calculating the siphon flow velocity was extended to the siphon operation mode with long horizontal sections

Study on Siphon Drainage Capacity of Slopes with Long-Horizontal Pipe Sections

Siphon drainage, which is applicable in engineering as one of the effective methods to maintain slope stability, has many advantages, including no additional power requirements, simple construction, and low construction cost. However, due to topographic constraints and high farmland occupation costs, most projects inevitably use pipes with a total length of more than 100 m and horizontal sections of more than 50 m for drainage. The increase in pipe length has serious adverse effects on the siphon drainage process, limiting its drainage capacity and long-term applicability. Therefore, in slope siphon drainage, drainage efficiency and long-term effectiveness are critical factors in determining whether a particular pipe size can be used effectively for slope drainage management. This paper investigates the performance of different pipe diameters in drainage capacity, flow regime, and restarting ability under different head and pipe length combinations through theoretical analysis and extensive foot-scale model tests. It was found that a 5 mm pipe diameter, as a transitional pipe diameter between capillary and typical pipe diameter, has both capillary and gravity-dominated characteristics under different capillary and Reynolds number conditions, which can form a stable segmental plug flow while maintaining the presence of liquid film and preventing increased frictional losses along the course

Systematic monitoring of the performance of anchor systems in fractured rock masses

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