CE En 540
Homework #5  

Geomembrane Design Calculations

1.  Geomembrane Slack

How much slack should be added to a 300 ft long strip of LDPE? Assume that the membrane is placed with the temperature at 90 degrees F and the membrane may be exposed to temperatures as low as 20 degrees F before insulating cover material is placed on the membrane.

2. Anchor Trench Design

Write a spreadsheet to that computes the runout length for an anchor trench given the anchor trench depth, anchorage ratio, depth of cover soil, etc.  Be sure to list the units for each parameter.  Make your spreadsheet as professional as possible.

Organize your spreadsheet so that there is an input section and a results section.  The sections should contain the following parameters/equations:
 

Input Parameters	Results
Anchorage ratio	TGS
Ult. strength of membrane	Fu
Membrane thickness	q
Depth of cover soil	Ko
Unit wt. of cover soil	Ave vertical stress in trench
Friction angle, membrane/soil	Ave horizontal stress in trench
Friction angle, soil	F(AT)
Unit wt of backfill	Runout length
Friction angle of backfill
Depth of anchor trench

Turn in a copy of your spreadsheet with a set of values corresponding to the example problem we worked in class.

Submittal Instructions:

When you finish your assignment, click here to upload it electronically to the TA for grading.