मेलम्ची सुरुङ्गमा Lugeon test र grouting work गरिदै गरेको अवस्था
Channel: Pusker
Date: 2020-12-13

A Lugeon is a unit devised to quantify the water permeability of bedrock and the hydraulic conductivity resulting from fractures; it is named after Maurice Lugeon, a Swiss geologist who first formulated the method in 1933. More specifically, the Lugeon test is used to measure the amount of water injected into a segment of the bored hole under a steady pressure; the value (Lugeon value) is defined as the loss of water in litres per minute and per metre borehole at an over-pressure of 1 MPa.
Although the Lugeon test may serve other purposes, its main object is to determine the Lugeon coefficient which by definition is water absorption measured in litres per metre of test-stage per minute at a pressure of 10 kg/cm2 (1 MN/m2).The waterflow which passing through the rock mass depends of some parameters such as: connection of system crack, cracks width, step of cracks filling, filling type and filling erosion resistance during waterflow.
The Lugeon test is an in- situ testing method widely used to estimate the average hydraulic conductivity in rock mass.
The test is named after  Maurice Lugeon, a Swiss geologist who first formulated the test.
Usually, on a certain section of borehole, there are installed packers through which a special pipe brings water under pressure. In the enterence of the borehole pressure is measured with the pressure gauge, and the flow is measured with the watermeter.Lugeon value could also represent the rock jointing conditions, considering a big influence of rock discontinuities condition on value of hydraulic condutivity.Typical range of Lugeon values and the corresponding rock condition .Test is typically conducted in five steps. At each step, a constant water pressure is applied for a duration of 10 minutes.
Permeability test – Lugeon test. Why we need permeability test?
Permeability test is necessary on terrain where are predicted soakaways which store water after big rainfall and provide efficient soil infiltration. Usually they are used in areas where surface run-off cannot be disposed into existing sewers or watercourses.
A Soakaway is constructed in one of two basic forms:
Conventional soakaway – comprises a partially perforated cylindrical or rectangular chamber, which allows the drainage of water into the surrounding soil.
Borehole soakaways – in cases where impermeable soils overlie the permeable strata, the soakage must take the place at depth and so a deep bore liner is used. Here the water is transported from a sealed storage chamber to the soakage medium by a small diameter plastic or steel pipe, again perforated in part.

Grout is a dense fluid which is used to fill gaps or used as reinforcement in existing structures.Grout is generally a mixture of water, cement, and sand and is employed in pressure grouting, embedding rebar in masonry walls, connecting sections of pre-cast concrete, filling voids, and sealing joints such as those between tiles. Common uses for grout in the household include filling in tiles of shower floors and kitchen tiles. It is often color tinted when it has to be kept visible and sometimes includes fine gravel when being used to fill large spaces (such as the cores of concrete blocks). Unlike other structural pastes such as plaster or joint compound, correctly mixed and applied grout forms a water resistant seal.
Also, it is used to strengthen fractured rock or soil and to render it impermeable. It can be applied under pressure to fill cracks and fractures to control water flow in a variety of applications such as beneath dams and around basements, mine excavations, as canals, tunnels, etc. In drilling it is used to prevent the flow of fluids between the well bore and the casing.Although both grout and its close relative mortar are applied as a thick emulsion and harden over time, grout is distinguished by its low viscosity and lack of lime (added to mortar for pliability); grout is thin so it flows readily into gaps, while mortar is thick enough to support not only its own weight, but also that of masonry placed above it. Grout varieties include tiling grout, flooring grout, resin grout, non-shrink grout, structural grout and thixotropic grout.Tiling grout is often used to fill the spaces between tiles or mosaics and to secure tile to its base. Although ungrouted mosaics do exist, most have grout between the tesserae. Tiling grout is also cement-based, and comes in sanded as well as unsanded varieties.[citation needed] The sanded variety contains finely ground silica sand; unsanded is finer and produces a non-gritty final surface. They are often enhanced with polymers and/or latex. Structural grout is often used in reinforced masonry to fill voids in masonry housing reinforcing steel, securing the steel in place and bonding it to the masonry.[3] Non-shrink grout is used beneath metal bearing plates to ensure a consistent bearing surface between the plate and its substrate.