I would inquire of the geotechnical engineer whether or not the ultimate passive pressure they provided has already been factored (reduced).
I approach cantilever pile designs like this by comparing resisting moment to overturning moment. I set the embedment depth such that the ratio of the...
I don't know where this project is but the soil properties you have assigned are very strange to me. They are not indicative of a deep open cut that has remained standing for 10 years. Were these values provided in a geotechnical report?
Applying the resultant toe reaction to the top of the lower soldier pile wall seems reasonable to me. However, I am concerned about what appears to be a very shallow toe embedment for the existing wall. You show lagging behind the back of your lower soldier pile wall. This means that for the...
I personally would never assume zero earth pressure unless I'm building against a very competent rock. I would ask others in your area what a safe assumption but not overly conservative equivalent K value would be. Unfortunately, geotechnical engineers can often be reluctant to give realistic...
I disagree that Ka=1 implies that is neither clay nor granular. To me, Ka=1 implies that the friction angle equals zero. For me, using a friction angle of zero and an undrained shear strength puts bounds to the problem. Undrained shear strength is the cohesion intercept which corresponds to...
Also, in my experience/local area of practice, when I get a theoretically negative pressure, I use a K value of 0.2 (this is just a made up, safe value). This is specific to my area. Ask around to see what is common practice where yoy are.
Yes, it is fairly common to get calculate negative active earth pressure for cohesive soils (at least in my area). A mathematically negative value would seem to imply that the soil is pulling away from your wall (whatever that might be). Instinctively, we know this isn't happening. Rather the...
When you say the slab has been supporting a live load for 20 years, do you mean a vehicular live load? What is the purpose of this slab? I would definitely be at ease about putting a skid steer on this slab if I knew the area was used for ploughs to stockpile snow or garbage trucks to pick up...
It is absolutely possible. Whether it is appropriate depends entirely on the loads which they must resist. I assume when you say only axial load, you mean only compressive axial load. If that's the case, I would research "rigid inclusions". This would usually fall under the heading of ground...
I have no idea what the access is like on this slope, what kind of loads you need to resist, or how remote this site is. However, there are many smaller drill rigs that can handle slopes better than the large, top-heavy drills often used on large infrastructure projects. Look up smaller drill...
Try to get your hands on a copy of Underpinning by Prentis and White. The Foundation Engineering Handbook by Winterkorn and Fang also has a good chapter on underpinning written by White.
Hmmm. 4ft is pretty tight pile spacing and should give the soil lots of opportunity to arch (unless the contractor does something silly like open all of the bays and chip away all of the soil behind the pipes all at once). But keep in mind, if your intent is to lag behind pipe piles, you will...
In my experience, it is best to avoid lagging within the influence of adjacent buildings and construct a tanget or secant wall as you previously suggested to your client (however, based on your sketch, it doesn't look like you have clearance for a tangent or secant wall). This is not for...
In my area, the sequence is to drill the soldier piles, drill the dewatering wells, draw down the water, then excavate.
I suppose in some areas, it may be preferable to draw down the water and then drill the soldier piles, but where I am the contractors are content to drill in wet ground with...
