Shafts, construction

The expander design will be of axial entry (Figure 5-14), overhung rotor, stiff shaft construction with one or two rows of blading designed and constructed for 100,000 hrs of life and at least 3 yrs of uninterrupted continuous service. It is recognized that uninterrupted operation for this period of time involves factors beyond the Seller s control. 

The critical values are generally obtained from a standard tensile test. Once the critical values are obtained the application of any (or all) of these criteria in conjunction with a dependable stress analysis is straightforward. Here we demonstrate the method by a simple example. Let us assume that it is desired to determine the torque required to cause failure of a 25 mm in diameter shaft constructed of an homogeneous isotropic plastic with a failure stress in tension, o, of 7 x 10 N/m. Assume further tlmt the modulus of elasticity, E, for this plastic is given by 3 x 10° N/m, and that is has a Poisson ratio of 0.3. We will explore the prediction of the three criteria just discussed. 

Sample preparation consists of two phases At first filed sampling will be carried out in long inclined-shaft construction area, as shown in Figure 2. And then, samples will be shipped to indoor laboratory for further processing based on the above detailed requirements. 

Figure 6.4. Drilled shaft construction in competent soils using dry method, (a) Drilling the shaft (b) Starting...

O Neill, M.W. Reese, L.C. 1999. Drilled shafts construction procedures and design methods. Federal Highway Administration. USA. 

Different shaft construction techniques has been considered / investigated ... 

The project group decided to recommend pilot hole, raiseboring and slashing to obtain a cost and time efficient shaft construction. This technique can also handle deviation in the pilot hole (if the pilot hole deviate from intended position, that can adjusted during slashing). 

A pilot hole and raiseboring to final diameter to obtain a cost and time efficient shaft construction was chosen. The external contractor used a Directional Drilling Technique (RVDS) to secure that the pilot hole deviates not more than 0.5m. 

The shaft diameter had been selected (6.1 m unlined) by the Client based on the shaft construction methodology using raise boring and the depth/diameter capability of the raise boring equipment available. 

The first step in groundwater control is the hydrogeologic assessments by estimating ground-water inflows and assessing the impacts to shaft construction and service performance as well as impacts to area surrounding shaft. 

Reese, L. C. and M. W. O Neil. 1988. Drilled Shafts Construction Procedures and Design Methods, U.S. Department of Transportation, Federal Highway Administration, McLean, VA. 

Touma, F. T. and L. C. Reese. 1972. Load Tests of Instrumented Drilled Shafts Constructed by the Slurry Displacement Method. Research report conducted under Interagency contract 108 for the Texas Elighway Department, Center for Highway Research, The University of Texas at Austin, January, 79 pp. 

Independent contractors performing construction on mine property often are hired to build buildings, sink shafts, construct plants and mills, lay railroad track, build dams, and build roads. Although construction contractors may be on mine property for a lengthy period, once their job is complete, this kind of independent contractor usually leaves the property. 

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