Please answer the following as soon as possible please make

Please answer the following as soon as possible. please make clear handwriting so i can read. typing is better. many thanks 1- Consider a site where the groundwater table is at the ground surface. Explain in words (no equations) why the vertical effective stress does not change if the groundwater rises above the ground surface 2- Convince me why the long-term (i.e. drained) strength is often more critical than the short-term (i.e. undrained) strength for over- consolidated clays? 3- Consider a sample of sand with an initial void ratio equal to critical (ecrit) subjected to a confining pressure less than critical How would you expect the volume of the sample to change when sheared under drained conditions? How would you expect the pore water pressure of the sample to change when sheared under undrained conditions? 4- Whydoover- consolidatedclaysexhibithigherpeakdrainedstrengthatlowerconfining stress compared to normally consolidated clays? What happens at larger confining stresses?

Solution

1. There are three types of stresses in soil. They are Total stress, Neutral stress or Pore water pressure and Effective stress. You asked for the vertical effective stress which is Total stress minus Neutral stress . In the case of rivers, lakes and etc., The Total stress is equal to Neutral stress because the unit weights and heights are equal. So, the vertical effective stress will be zero. My suggestion is do one simple problem on this and you will get it.