According to legend, eagles picked up tortoises and attempt to crack them open by dropping them on rocks.

根据传说，老鹰抓了乌龟，为了弄开它们的壳，会将其扔到岩石上。

youdao

The crack distribution and evolution of the surrounding rocks of roadway can be quantitatively depicted by the fractal dimension of crack density.

用裂隙密度分形维数定量描述了巷道围岩裂隙的分布和演化。

youdao

Gas pressure from gas dissolved in the magma also exerts force on the surrounding rock. It cracks the rocks above the magma and then moves into the crack.

而溶解在岩浆的气体亦会对周边的岩石施加压力，令这些岩石破裂，这些气体从而渗入岩缝内。

youdao

Shale gas is natural gas that is trapped inside shale rock and is extracted by using a technology called hydraulic fracturing, where highly pressurized water mixed with sand and chemicals is used to crack open rocks.

FORBES: Will ConocoPhillips Help China Tap Its Shale Gas Reserves?

Rather, as a consequence of injecting water and sand into the shale formation to crack the rocks so gas and oil will flow, massive amounts of waste water comes back to the surface with significant amounts of contaminants as a result of leaching out salt, heavy metals and trace amounts of radioactive materials from the rock formation itself.

FORBES: U.S. Energy Independence - So Close, Yet So Far

Hydraulic fracturing or "fracking" is a process of forcing water mixed with chemicals through deep wells to shatter and crack hard shale rocks to release the gas inside.

BBC: Hydraulic fracturing