Dmc Pile Method Full video скачать в хорошем качестве

Dmc Pile Method Full video

DMC Piling 1. INTRODUCTION Piles are the columnar structure, the most common type of deep foundation, that safely transfer loads from the super structure to more competent subsurface strata by means of friction, end bearing or a combination of both. Piles can be broadly classified based on the following parameters. 1. Method of installation of piles – Driven (displacement) piles or bored (replacement) piles. 2. Type of material used for piling – Concrete, steel, timber piles etc. Among these, concrete piles can be classified further as pre- cast and cast in situ concrete piles. Though there are a variety of piling options, the most common type of piles used for majority of construction works in India are bored cast in situ concrete piles. way. Displacement piling is good for contaminated sites where it costs a lot to move the soil out. Using the replacement piling method, muck is dug out and replaced with the pile. Much bigger piles can be casted by replacement method. Direct Mud Circulation (DMC) piling method or simply DMC Piling method is an example of replacement piling method. This method is the principle subject of interest in this report. The advantages of displacement piling are:-  Self testing as driven to refusal or "set"  No pile arising to dispose of  Little disturbance  Limited access  High production The disadvantages of displacement piling are:-  Cannot penetrate obstructions  Cannot always penetrate desiccated clay  Vibration and noise may be an issue The advantages of replacement piling are:-  Effectively vibration free  Installed into non cohesive and water bearing soils  High production  Restricted access The main disadvantage of replacement piling is that:-  it produces excavated material which requires removal off site 3. Principle of DMC piling DMC piling is a typical wash bored piling method, ie. the piles are of REPLACEMENT type. For this type of piling method, the sub soil must be of cohesive nature. The basic principle of DMC piling lies in the fact that the soil layers becomes harder to penetrate with depth, so to soften the hard soil layers deep below the ground level, water jet streams are used and then a typical chisel cuts the relatively softer soil. Bore holes of several depths (for example 10m, 15m, 20m, 25m, 30m, etc.) and diameter (for example 500mm 750mm, 1000mm etc.) are dug as per design requirements. It can be understood quite clearly that the nearby soil can collapse. To prevent the collapse some special safety measures are considered during the operation which will be discussed in later sections. After the bore hole is dug and the collapse of subsoil around the hole is safely prohibited, a reinforcement cage is entered into the borehole and concrete is filled from the bottom of the hole with the help of pipes, typically designed for this operation, called the Tremie pipes. Usually concrete is left 28 days to harden and gain full strength, but sometimes using admixtures they are prepared within 21 days. 4.Apparatus used I. DMC rig  THE TRIPOD SYSTEM Main shear leg: it is the longer leg than the other two that carries the load. The length is 7.5m. The length can be adjusted. With the help of 20mm dia pins The side shear legs: there are two side shear legs, 6.3m long and they mainly support the tripod system. The side legs must be placed at least 1.5m away from the centre of the piles.  BASE CHANNEL These are standard I section, 2cm thick and there are grooving in it that holds the shear legs onto the ground with the help of base cannel pin.  SLIP OVER WHEEL Diameter 450mm Thickness 50mm Operation The rope slips over this wheel or Pulley  SLIP OVER WEEL HOLDER Diameter = 500mm  S.O. WHEEL PIN Diameter 65mm Length 200mm Operation This is very important pin, because it holds the S.O. Wheel with the tripod system and the entire vertical loads act on it.  PLUNGE Inside Diameter = 50mm  SUSPENSION PLATE – this is called into action if somehow the chisel is stuck in the borehole. Pulleys are attached here and the chisel is pulled out. Suspension Plate  MAIN SHEAR LEG PIN – 20mm dia. The whole system is pulled up by the rope and the D-Shackle with the help of the winch system and then left to fall free, so that the chisel at the bottom cuts the soil and the boring progresses.  The loose soil produced by boring, mixes with water and comes up and is stored in the wash vat, where the soil gets precipitated and the water is again usable. Taking out of the DMC rods and Chisel and Insertion of the reinforcement cage  After the boring is complete up to the desired depth, the DMC rods are removed one by one using the DMC fork and the chisel is also removed.  Then the steel reinforcement cage is inserted and welded where ever there are joints.  Concreting and finalization of the process