A soil element is 2m below ground surface. It has a vertical effective overburden stress of 30kpa, an overconsolidation ratio of 4. Compression index of 0.2, recompression index of 0.04. and an undrained shear strength of 18kpa as determined by ko consolidated undrained triaxial compression test. Soil element is subsequently been consolidated under vertical surcharge load of 130kpa. Estimate the undrained shear strength of soil after soil is fully consolidated under 130kpa surcharge load