RS-13-009, Clinton, Unit 1, Updated Safety Analysis Report, Revision 15, Chapter 2 - Site Characteristics, Figures 2.5-300 Through 2.5-496
| ML13016A313 | |
| Person / Time | |
|---|---|
| Site: | Clinton  |
| Issue date: | 01/10/2013 |
| From: | Exelon Generation Co |
| To: | Office of Nuclear Reactor Regulation |
| References | |
| RS-13-009 | |
| Download: ML13016A313 (264) | |
Text
NOTES FOR FIGURE 2.5-300 Method of Performing Direct Shear and Friction Tests Direct shear tests are performed to detemine the shearing strengths of soils. Friction tests are performed to determine the frictional resistances between soils and various other materials such as wood, steel, or concrete. The tests are performed in the laboratory to simulate anticipated field conditions.
Each sample is tested within three brass rings, two and one-half inches in diameter and one inch in length. Undisturbed samples of in-place soils are tested in rings taken from the sampling device in which the samples were obtained. Loose samples of soils to be used in constructing earth fills are compacted in rings to predetermined conditions and tested.
Direct Shear Tests A three-inch length of the sample is tested in direct double shear. A constant pressure, appropriate to the conditions of the problem for which the test is being performed, is applied normal to the ends of the sample through porous stones. A shearing failure of the sample is caused by moving the center ring in a direction perpendicular to the axis of the sample. Transverse movement of the outer rings is prevented.
The shearing failure may be accomplished by applying to the center ring either a constant rate of load, a constant rate of deflection, or increments of load or deflection. In each case, the shearing load and the deflections in both the axial and transverse directions are recorded and plotted. The shearing strength of the soil is determined from the resulting load-deflection curves.
Friction Tests In order to determine the frictional resistance between soil and the surfaces of various materials, the center ring of soil in the direct shear test is replaced by a disk of the material to be tested. The test is then performed in the same manner as the direct shear test by forcing the disk of material from the soil surfaces.
CLINTON POWER STATION UPDATED SAFETY ANALYSIS REPORT Figure 2.5-300 Sheet 2 of 2 DIRECT SHEAR AND FRICTION TESTS (METHOD)
NOTES FOR FIGURE 2.5-301 Methods of Performing Pulsating Load Triaxial Tests Pulsating axial load tests are performed to evaluate the dynamic properties and the liquefaction potential of the soils under simulated anticipated field loading conditions.
Pulsating load tests are stress controlled and are performed on undisturbed or reconstituted samples of soil approximately six inches in length and two and one-half inches in diameter. The samples are encased in a rubber membrane, placed in a test chamber, and subjected to confining pressure throughout the duration of the test. The tests may be run on soils at field moisture content or on artificially saturated samples. The triaxial equipment acting through a Bellofram system applies a pulsating axial load. The cycling speed of the load can be varied between one-half to five cycles per second to simulate the field loading frequency. Dynamic Properties Determination To evaluate the dynamic parameters, the soil sample is loaded in cyclic compression. The load and deflection are recorded on two channels of a recording oscillograph. By tappi ng the output of the load and deflection transducers and applying these to vertical and horizontal plates, respectively, of a cathode ray oscilloscope, a hysteresis loop is produced. This loop is photographed, and the photograph is used to evaluate the damping value present. The procedure is repeated at various strain amplitudes to evaluate the dynamic properties in the range of interest on a particular sample. The load and deflection values obtained from the oscillograph are used to evaluate the dynamic moduli of elasticity.
Liquefaction Potential To evaluate the liquefaction potential, the soil sample is subjected to axial cyclic loading, the magnitude, frequency, duration and sequence of loading is determined on the basis of past earthquake records. The load deflection, and pore pressure are recorded on three channels of a recording oscillograph. These records are used to evaluate the liquefaction potential for that particular soil type under the test conditions.
CLINTON POWER STATION UPDATED SAFETY ANALYSIS REPORT Figure 2.5-301 Sheet 2 of 2 PULSATING LOAD TRIAXIAL TEST (METHOD)
Method of Performing Resonant Column Tests Resonant column tests are performed to determine the dynamic properties of soils under high frequency, small amplitude cyclic strains. The test is based on the fact that analytical solutions can relate the stiffness of the soil column to its resonant frequency. In the test the sample is excited by an oscillating device and the frequency is varied until the maximum response, or resonant frequency, is found.
The Dames and Moore resonant column apparatus subjects solid cylindrical samples to torsional oscillations. The sample base is fixed and the top of the sample is excited by a Hardin oscillator which is driven by a variable frequency sine wave generator. The response of the sample is measured by an accelerometer mounted in t he oscillator and the output is displayed on an oscilloscope.
The equivalent linear shear modulus of the soil is obtained from the resonant frequency of the system after the manner suggested by Drnevich and Hardin ("Proposed Standard for Modulus and Damping of Soils by the Resonant Column Method", ASTM Committee D18.09, May 1974). The shear modulus of soils varies with the shear strain amplitude and thus actually varies along the radius of the sample but in calculating the shear modulus the average shear strain is taken to correspond to the cyclic shear strain developed two-thirds of the distance along the radius. The damping ratio at small strains may be computed from measurements of the logarithmic decrement which are obtained by subjecting the sample to a steady state oscillation and then shutting off the input voltage. The decay curve is retained on a recording oscilloscope and may be photographed to make a permanent record.
CLINTON POWER STATION UPDATED SAFETY ANALYSIS REPORT Figure 2.5-318 Sheet 2 of 2 RESONANT COLUMN TESTS (METHOD)
Method of Performing Consolidation Tests Consolidation tests are performed to evaluate the volume changes of soils subjected to increased loads. Time-consolidation and pressure-consolidation curves may be plotted from the data obtained in the tests. Engineering analyses based on these curves permit estimates to be made of the probable magnitude and rate of settlement of the tested soils under applied loads.
Each sample is tested within brass rings two and one-half inches in diameter and one inch is length. Undisturbed samples of in-place soils are tested in rings taken from the sampling device in which the samples were obtained. Loose samples of soils to be used in constructing earth fills are compacted in rings to predetermined conditions and tested.
In testing, the sample is rigidly confined laterally by the brass ring. Axial loads are transmitted to the ends of the sample by porous disks. The disks allow drainage of the loaded sample. The axial compression or expansion of the sample is measured by a micrometer dial indicator at appropriate time intervals after each load increment is applied. Each load is ordinarily twice the preceding load. The increments are selected to obtain consolidation data representing the field loading conditions for which the test is being performed. Each load increment is allowed to act over an interval of time dependent on the type and extent of the soil in the field.
CLINTON POWER STATION UPDATED SAFETY ANALYSIS REPORT Figure 2.5-319 Sheet 2 of 2 CONSOLIDATION TESTS (METHOD)
NOTES FOR FIGURE 2.5-347 Methods of Performing Percolation Tests The quantity and the velocity of flow of water which will escape through an earth structur e or percolate through soil are dependent upon the permeability of the earth structure or soil. The permeability of soil has often been calculated by empirical formulas but is best determined by laboratory tests, especially in the case of compacted soils.
A one inch length of the core sample is sealed in the percolation apparatus, placed under a confining load, or surcharge pressure, and subjected to the pressure of a known head of water. The percolation rate is computed from the measurements of the volume of water which flows through the sample in a series of time intervals. These rates are usually expressed as the velocity of flow in feet per year under a hydraulic gradient of one and at a temperature of 20 degrees Centigrade. The rate so expressed may be adjusted for any set of conditions involving the same soil by employing established physical laws. Generally, the percolation rate varies over a wide range at the beginning of the test and gradually approaches equilibrium as the test progresses. During the performance of the test, continuous readings of the deflection of the sample are taken by means of micrometer dial gauges. The amount of compression or expansion, expressed as a percentage of the original length of the sample, is a valuable i ndication of the compression of the soil which will occur under the action of load or the expansion of the soil as saturation takes place.
CLINTON POWER STATION UPDATED SAFETY ANALYSIS REPORT Figure 2.5-347 Sheet 2 of 2 PERCOLATION TEST (METHOD)
CPS/USAR CHAPTER 02 REV. 12, JAN 2007
FIGURE 2.5-380 HAS BEEN DELETED
CPS/USAR REV. 9,January 2001
Figure 2.5-383 Deleted
CPS/USAR CHAPTER 02 REV. 15, JANUARY 2013
FIGURE 2.5-484 HAS BEEN DELETED
CPS/USAR REV. 9,January 2001
Figures 2.5-493 through 2.5-495 Deleted