What is cross passage?

What is cross passage?

A cross passage is a short tunnel that connects 2 parallel tunnels. These passages are an important safety feature that allow people (including emergency services) to move from one tunnel to the other in the event of an emergency.

What is a cross passage in tunnel construction?

Running tunnel cross passages are short tunnels that connect the two running tunnels. Their purpose is to allow access from one tunnel to another in an emergency or for maintenance purposes. The Crossrail running tunnels were mined and constructed using TBMs and the cross passages were built after the running tunnels.

What is dewatering in tunnel?

The purpose. of a tunnel dewatering program may be any one of the fol- lowing: To lower the water level so that the static compressed. air pressure required to conduct mining operations is within.

What is crossover in underground metro?

The Crossover TBM facilitates quick modification in the cutter head for changing it for different geological conditions. This helps it perform better in different ground conditions. The cutterhead is the front part of the TBM that has blades, which actually cut the rock to create the tunnel.

Which pump is used in tunnel drainage system?

The horizontal, single-stage, split-case, double-suction volute pump is the one most often used in tunnel fire protec- tion systems.

What is pre drainage?

Pre-drainage is widely accepted and performed to prevent and control methane-related disasters in Chinese outburst mines. Boreholes for pre-drainage are drilled directly into the outburst-prone seams and are theoretically able to capture most of the seam gas that has a high concentration of CH4.

What equipment is used for dewatering?

Dewatering Methods These include centrifuges, filter presses, drying beds, sludge lagoons, and gravity and low pressure devices.

What pumps are used for dewatering?

Efficient dewatering requires a reliable pump that can remove water from deep inside the ground. There are various dewatering pumps available, ranging in types including submersible pumps, centrifugal end-suction pumps, and well-pointing piston pumps.

What is dewatering in construction?

Dewatering is defined as the intentional removal of groundwater or surface water from a location. Natural evaporation aside, a dewatering process typically involves removing surface or groundwater from the construction site by pumping.

What are pumping equipments?

Introduction. Pumps and dewatering equipment are used to remove water from a volume of liquid, solid material or soil. Pumps simply remove liquid from a volume of liquid, whereas dewatering equipment separates water from another material such as soil or sludge.

What is a dewatering system?

Dewatering refers to the process by which water is removed from solid materials. This drainage system will direct the water to a sump pump, which then discharges the water from the home and downhill away from the house, effectively protecting the home.

What are the types of dewatering system?

There are four important dewatering methods one should be aware of:

• Wellpoint method of dewatering,
• Eductor wells,
• Open sump pumping and.
• Deep wellpoint method.

Can multiple dewatering wells be used to dewater the excavation?

Richard constructed a groundwater model to perform parametric analyses of various dewatering scenarios. The modeling results indicated that a design consisting of multiple dewatering wells in different soil formations could effectively dewater the excavation while reducing the potential risk of adverse affects during construction.

What is required to design a dewatering system?

Design of a dewatering system requires the determination of the number, size, spacing, and penetration of wells or wellpoints and the rate at which water must be removed from the pervious strata to achieve the required groundwater

What is a cross passage in rail?

Cross passages are positioned between permanent shafts, portals and stations such that the spacing between opportunities to cross from one track to another is in the range 600m to 800m. In many cases the cross passages replaced permanent intervention and escape shafts that were initially proposed for Crossrail.

What is the relationship between stations and cross passages?

These relationships are set out in the table. Cross passages are positioned between permanent shafts, portals and stations such that the spacing between opportunities to cross from one track to another is in the range 600m to 800m.