Soldier Piles on sloped ground 1

[Kuhuh]

I got a new design that I have not come acrossed yet before. The client wants a soldier pile system to temp shore an access path for construction vehicles into a already graded excavation site. The slope of the already graded site is 1.5:1 (H:V). The exposed shored wall is already at 10' high but the resistant soil is sloping 1.5:1 away from the face of the shoring. See attached photo for clarification. My question is how much soil do I need as resistant soil. Calculate enough to counter the force? I have a feeling this will be 20'+ leaving the entire soldier beam as 30'+ long. What are your thoughts?

http://files.engineering.com/getfil...8dd-4a63-9fd5-9ab124d6a06a&file=shoring_2.pdf

http://files.engineering.com/getfil...-d0a6-4bcc-91b0-56d1b87b7844&file=shoring.pdf

 

[GeoPaveTraffic]

Your embedment length will need to be greater. How much will depend on the loads and how close the slope is to the wall.

This link is for retaining walls. You should be able to adapt it to your needs.

http://web.mst.edu/~rogersda/umrcou...ion of Earth Pressures on Retaining Walls.pdf

Mike Lambert

 

[BigHarvey]

Don't forget you will need a horizontal working platform for the drilling rig.

 

[Kuhuh]

Correct obviously tie back is the only option for this situation. I have never done one with a decreasing passive area. I am still pretty much a greenhorn to designing shoring( I submit my designs to the senior engineer and he approves them so dont worry ) Would anyone have an example of this situation? The above reference mentions the situation and how it reduces the passive loads but I am having a hard time finding references on how it directly effects it.

 

[FixedEarth]

Bowles has a method of computing passive resistance in descending slopes. In general, embedment is about 1.3H for flat backfill and no surcharge. In your case, it may approach 1.6H +/-, so you 20 ft is on the safe side. For your case, you also need to check for daylight distance. Try achieving H/3 and a minimum of 10 ft of daylight distance as measured from the tip of the drilled pier. H is the slope height. Don't forget your traffic surcharge.

 

[Kuhuh]

I will have to check it. I just checked it for using apparent earth pressures in which the book does not contain any information about. I think as for safety I will be using Ko (at-rest) coefficient due to the traffic loads that it will be exposed to D8's 10 yd concrete trucks and the soil being class C and they only want 1/2" deflection at most so I am thinking rigid therefore my reasoning to use Ko. Any thoughts?

 

[msquared48]

You really need to contact your Geotech on this one and get his recommendation.

Mike McCann
MMC Engineering

http://mmcengineering.tripod.com

 

[RFreund]

FixedEarth - What is daylight distance?

Thanks.

EIT

 

[FixedEarth]

Daylight distance is the horizontal distance from the bottom of the pier tip to the outside face of the slope ( where you can see daylight ) For structures in or near slopes, we go by IBC figure which asks for H/3. Sometimes this H/3 is say 6 ft, so I always ask a minimum of 10 ft.

 

[RFreund]

Makes sense, thanks.

EIT