A section of an un-shored trench wall collapses. The collapsed wedge of soil measures 2 meters long, 1.5 meters deep, and 1 meter wide. The soil density is 1,900 kg/m³. Calculate the weight of the soil that fell on the worker.

A trench shield (box) must be selected for an 8-foot deep trench in Type C soil. The soil unit weight ($\gamma$) is 120 lbs/ft³, and the active earth pressure coefficient ($K_a$) is 0.4. Calculate the maximum lateral earth pressure at the bottom of the trench.

The same 8-foot trench now has a heavy excavator parked right on the edge, adding a uniform surcharge load ($q$) of 500 psf to the adjacent soil surface. Calculate the new maximum lateral earth pressure at the bottom of the trench.

A utility contractor is digging a 6-foot trench in previously disturbed soil (an old landfill area). The soil looks like solid clay, so the foreman visually classifies it as Type A and benches the sides at a steep 3/4:1 slope. The trench collapses.

Workers are repairing a water main in a 4.5-foot deep trench in stable soil. The supervisor decides no trench box or shoring is needed because it is less than 5 feet deep. However, ground water begins seeping in rapidly.