Ground improvement support for PE pipe on mud soil 1

[bnard]

Hi guys hope you can help me with this. We are to relocate the existing 375 AC pipe at the toe of the road batter by laying a new 400 PE mainline about 25m from its original location. The road will be upgraded into 4 lanes and the existing ground is mud soil about 2-4m depth. Here are my queries.
1. What is the best effective protection strategy in laying the new PE mainline
2. The AC pipe has been there for more than 30 yrs and it is expected that settlement has already been taken place but there are section in the road upgrade where immediate road approaches will cross over the AC pipe and that portion of pipe will not be relocated. How shall we protect them from the additional loading that it will carry. Will concrete slab be adequate enough to distribute the loads on the sides?

Help guys pls thanks

 

[civilperson]

Details are required for good answers. Depth of cover over pipe? Class of bedding? Traffic loads? Soil strength and classification?

 

[bnard]

The road is a major highway linking most of the industrial warehouses and coal terminal plants within the industrial zone. It is projected to carry 15,000 AADT in 10-15 yrs time but currently the daily traffic is at 7,000 AADT. The depth of cover is 1.0m. Additional soils test is being undertaken at this stage.

 

[rconner]

I am curious what is the service?

 

[bnard]

the service is a raw water mainline

 

[rconner]

While not presuming to make such decisions, I wonder in this day and time, assuming the buried pipe is basically pretty much accessible at the time the new road approaches are constructed, how many utilities would really want to build new civil engineering infrastructure over a section of old, rather shallow-buried asbestos cement water piping (ACP, it appears intended to deliver eventually potable water) encased in mud? It might make more sense to improve the bedding/road base however necessary for like constructiojn under roads, and (carefully) also replace the ACP in that area as well at the time.

 

[bnard]

thks guys

the ACP is 30 yrs old which is really a bit old and to my understanding has already induce settlement due time and might as well be very brittle and any adjacent additional loads or lateral stress is unadvisable. Only a portion of which will be replaced around 2km and the new PE pipe will be connected back to ACP mains.