Construction & Contractors/Bedrock


Are there ways to remove bedrock without blasting or jack hammering.   I heard reference to a process "Japanese Dynamite"

Using a material that expands and breaks up rock.  Thanks

There are expansive grouts that go by the trade names Dexpan, Da-Mite, Bristar, and some others.  They can be tricky to get to work but if you follow the instructions to the letter, paying particular attention to the temperature compatibility requirements, you can break rock or concrete effectively.  One thing to remember is that you do have to drill a lot of holes in the rock with that stuff.  In addition to the working temperatures, you also have to consider the strength of the rock:  these grouts work great on concrete which is typically 3,000-4,500 psi compressive strength but when dealing with rock that may be upwards of three times that, you really have to downsize the work required of each hole, meaning you drill a lot of holes.

There are non-blasting propellant-based solutions that do not require an ATF high explosivews permit to use.  The BoulderBuster, RocKracker system, and others are examples.  Once again you have to drill a lot of holes, and you have to buy the system and fill out some paperwork.  You might be able to find a local earthmoving contractor that has these.

There are hydraulic splitters that can be used.  This involves an external electric-powered pump that delivers hydraulic fluid to the splitter unit, which is basically a cylinder that pulls a wedge up between two leaves.  The wedge and leaves are inserted into the rock and when activated the wedge expands the interior of the hole and it breaks the rock.  There are many rock excavation and stabilization contractors that have these.  The hole diameters are typically less than 2 inches and the spacings are typically less than 30 inches, so you do use a lot of holes.

In Peru I saw a practice where the locals break boulders in river channels by drilling holes on close centers and pack them full of dry leaves -- I think banana -- and when the river floods the leaves expand, fracturing the rock between the holes.  In other cultures they build very hot fires next to the rock, get it really hot, and throw cold water on it; the thermal shock breaks the rock.

So you have options.

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Robert Cummings, P.E.


I can answer questions related to rock blasting, rock and soil excavation (such as tunnels and highway cuts), stability of such excavations, and foundations in rock and soil. I can also answer questions related to geology and mining.


30+ years as a geotechnical engineer and minerals engineer. Active consulting practice in rock blasting, geotechnical engineering, and rock mechanics for mining and heavy construction.

Society of Mining Engineers, Deep Foundations Institute, Association of Engineering Geologists, and International Society of Explosives Engineers.

Mining Engineering, AEG Bulletin.

BS and MS Geological Engineering

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