Approach according to precise lithology shipment
In the process of stone blasting, the new actual and you can mechanized properties of stone is actually definitely one of one’s head affairs that dictate the result away from material blasting 21 . There clearly was often an unclear understanding that the brand new more difficult the fresh new stone, the fresh new more complicated it’s to be blasted in the modern technology globe. However, this new blasting perception is not just as expected when you look at the technologies techniques. Alternatively, it has been found that new hardness of material is not highest because unit consumption of explosives is actually highest twenty-two .
According to the cracking method of rock blasting 23 , the power put out of the explosives acts on the rocks because of the shock revolution and you will extension tension from detonation gas whenever an explosive explodes to your stones. A perfect depletion regarding rocks is due to the action stress created by the fresh new rush exceeding the electricity maximum, and this reveals that the fresh crushing state is actually directly associated with the brand new explosion opportunity while the mechanical attributes of your material. This means, underneath the specific standards out of tool volatile application means, style of, and free epidermis, the fresh new charge amounts is generally dependent on the fresh new technical features of material to reach a certain smashing perception. Hence, the new lithology shipment is considered the first reason for determining the device use of explosives twenty-four .
Into the an out in-depth study of the fresh lithology off hard rock, it’s learned that large stress possess a critical affect the brand new blasting procedure and rock cracking impression. The outcomes plus reveal that large-website fret unloading and you may blasting loading are not one or two separate process, on the contrary, they work inside synergy, and dynamic unloading keeps a critical perception twenty five . Thus, the fresh delivery from hard rock is key into construction regarding a segmented fees for blasthole.
Group from blasthole stone strata
On the antique blasting techniques, the latest 
lithology distinction along side blast gap breadth isn’t noticed on blasting construction. Thus, a single costs build are implemented. In the layered stone mass with delicate and difficult inclusions, the fresh weakened interlayer’s compression and tensile opposition stamina have become lower compared with you to in the advanced rock formations, nearly minimal. During the time, new weak interlayer can easily become the overflow station of your detonation gas and you will weaken the new smashing and throwing effect of the fresh new high-tension energy produced by the brand new explosion. Concurrently, in the case of high hard rock as opposed to burst splits, it is challenging to crack considerable stones utilizing the supplementary crushing principle out of take off stone accident on organizing procedure owed to help you a faltering interlayer twenty-six . Hence, this new section off soft rock and difficult rock is an essential step on the construction strategy.
The lithology data of the corresponding blastholes are obtained by intelligent drilling rigs. According to the hardness of the lithology, the blasthole rock strata are divided into 7 categories, and lithology classification numbers range from Type 1 to Type 7 27 . In order to facilitate the design and calculation of blasthole charge structure, the adjacent strata with similar lithology are combined and grouped. The lithology is divided into two groups of soft rock and hard rock, denoted as \(s\) and \(h\) , respectively. The classification rule of soft rock and hard rock is that the strata numbered 1, 2, 3, and 4 are soft rocks, and rock strata numbered 5, 6, and 7 are hard rocks. The grouping diagram of blasthole rock strata is shown in Fig. 4: H refers to the blasthole depth, Rs means the thickness of soft rock, and Rh means the thickness of hard rock.