1.032/1.361/1.366  Geomaterials & Geomechanics

HW 11 Office Hrs

Hi Class

Due to requests and scheduling problems, I'm going to move the office hours on Mon Dec 12 to 5-6 pm. Hopefully this works better for everybody.

Amy

Announced on 08 December 2011  10:01  a.m. by Amy Lynn Adams

Homework 11 Office Hours

Hi Class

The homework is still due Thursday, however we won't be collecting it until Tuesday because there is no class on Thursday. Therefore, everybody gets a free pass to Tuesday, even if you've already used yours.

To this end, I have had requests for an extra office hours session on Monday. We'll try for a short session 4 - 5 pm on Mon Dec 12.

For those who would like to hand their homeworks in this week instead of at Tuesdays class, please let me know and we can make arrangements.

Amy

Announced on 07 December 2011  3:26  p.m. by Amy Lynn Adams

Last TA office hrs Thurs 6-7:30

Hi Class
Reminder that the last TA office hours (HW 11) will be this Thursday from 6-7:30, not 4-5:30 like I mistakenly told some of you yesterday. Rm 1-353 as usual.

Amy

Announced on 29 November 2011  8:18  a.m. by Amy Lynn Adams

Internal Method Clarification

Hi Class

Many of you have asked me to clarify the internal and external methods for calculation of effective stress with seepage. In particular, there is confusion with the ‘qs’ term, what it represents and how to calculate it.

‘qs’ is an effective surcharge applied to an element under analysis. Think of it as a boundary effective stress. The internal method is calculated as σ’=qs+γbL+J. See the notes for a more thorough description of the terms. It helps if you draw a free body diagram (FBD) and think about from a force balance point of view. Be careful to get the directions of each force correct in order to get the signs in the above equation correct.

Consider a layer of clay below a layer of gravel, with downward flow. There are 4 forces acting on a unit area element of the clay layer: The weight of the layer (buoyant weight term) acting down, the seepage drag force (J term) acting down, the qs term acting down, equal to the effective stress or net stress acting down at the top of the clay layer due to the gravel weight, and finally the effective stress at the base of the clay layer acting upwards. The internal method is therefore just a simple calculation balancing forces.

The external method is also a force balance but it is based on pore pressures and total stresses and is more closely linked with ‘effective stress equation’, σ’=σ-u. The two methods calculate the same thing.

I hope this helps for the weekend.

Amy

Announced on 29 October 2011  10:12  a.m. by Amy Lynn Adams

Office Hour Schedule

The following is the office hour schedule for the remainder of the term. Please note changes from regular times, especially for HW6 and HW11.

HW 4 –Office Hours Wed Oct 19, 4 – 5 pm (Due Th. Oct 20) *Note time adjustment due to make up lecture scheduled Wed Oct 19 5-6:30
Midterm Review: Wed Oct 26, 5-6:30
HW 5 –Office Hours Mon Oct 31, 4-5:30 (Due Tu. Nov 1)
HW 6 – Office Hours Fri Nov 4, 4- 5:30 (Due Tu. Nov 8)
Note: I am away Nov 6 – Nov 13.
HW 8 – Office Hours Mon Nov 14, 4-5:30 (Due Tu. Nov 15)
HW 9 – Office Hours Mon Nov 21, 4-5:30 (Due Tu. Nov 22)
HW 10 – Office Hours Mon Nov 28, 4-5:30 (Due Tu. Nov 29)
HW 11 – Office Hours Thur Dec 1, 6-7:30 (Due Thur Dec 8)
Note: I am away Dec 3 – 10th.

Amy

Announced on 17 October 2011  9:02  a.m. by Amy Lynn Adams