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�^,8.B. - Page 126 5-Lot Residential Development December 9, 201 Q <br /> � <br /> 1r <br /> C� = factor to nortnalize N�to a common reference effective over-burden stress <br /> CE = hammer energy ratio{ER)correction factor <br /> C� = borehale diameter correction factar <br /> C� = zod length correction factor <br /> CS — correction factor for samplers wrth or without liners <br /> �actor E ui menf Variable Term '�Correction <br /> Overburden Pressure CN (pa�6'„a)o s ; 0 q<CN�2 <br /> Energy Itatio Safety Hammer 0.60 to 1.17 <br /> Donut Hammez CE 0.45 to 1.00 <br /> AutomaYic Tri Hammer 0.9 to l.b <br /> Barehole Diameter 65 mm to 115 mm 1.0 <br /> 150 mm CB 1.05 <br /> 200mm 1.15 <br /> Rod Length 3m to 4m 0.75 <br /> 4m to 6m 0.85 <br /> 6m to lOm CR 0.95 <br /> lOra to 34m 1.0 <br /> >30 m �1.0 <br /> Sampling Method Standard Samplez- C 1.0 <br /> Sampler without liners � S i.2 <br /> The other steps involve obtaining two ixnportant varzables: the seismic dexzaaxzd on a sozl layer, <br /> expressed in tez-�ns of CSR {known as cyclic stress ratio}, and the cap�city of a soil layex to resist <br /> liquefaction, expressed in ternls of CRR(known as cyclic resistance ratio). <br /> CSR car��e calculated using the following equation: <br /> GSR=�tia�6�vo�_�.65\anzac�g�l6vo'6�w�rd <br /> vvhere <br /> a�„� =peak horizontal acceleratio�at the girouz�d su.rface generated by the earthquake <br /> g =acceleration of gravity <br /> 6,,0 =totaI vertical overburden stress <br /> 6'„a =effective vertical over6urden stress <br /> rd =stress reduction coefficient <br /> CRR can be obtained from the Simplified Base Curve recommended for determinatian of CRR <br /> frarn SPT for Magnitude 7.5 alon.g with Eznpirical L'aquefaction Data (after Youd and Idriss <br /> 1977}. <br /> A factor of safety (�'S) against liquefaction is then calculated using the following equation: <br /> FS=(CRR�.SICSR)MSF <br /> 6 <br />