Trench Digger

a machine for digging drainage ditches and irrigation channels, trenches, ditches along roads, and so on. There are trench diggers with moving parts (rotor or cutter) and nonmoving parts (plow or moldboard), as well as trench diggers with combined elements (for example, with a moldboard and rotor or with a rotor, auger, and multiscoop unit).

Cutters or rotors are mounted on a tractor, trailer, or self-propelled chassis. Trench diggers with one or two cutters are used for making drainage ditches 0.5-2 m deep in swampy-peat soils. The cutters turn at up to 30 m per sec; such a velocity is necessary to create a cutting force, break up vegetation and peat, and throw the dug-up earth up to 20 m away. Rotor trench diggers are used to make irrigation ditches up to 2 m deep in dense soils. The rotors turn at speeds up to 8 m per sec. The earth is thrown a short distance and is often used to form dikes. Depending on the type of earth and the cross section of the ditch, cutter and rotor trench diggers require one or several passes to complete the channel. The productivity of cutter and rotor trench diggers varies between 80 and 800 cu m per hr.

Plow (trailer or mounted) and moldboard trench diggers make channels using the tractive force of the tractor. The working element of plow trench diggers is a double-moldboard plow which, moved by one or several tractors, makes a channel 0.4-1.2 m deep in one pass and can move up to 1, 800 cu m per hr. The working element of the moldboard trench digger is two symmetrical grader-type moldboards that work the soil by layers, shaping the bottom and walls of the channel with a productivity up to 1, 500 cu m per hr.

Trench diggers with combined working elements make a channel up to 3 m deep in one pass and grade the bottom and walls. Each of the working elements works a specific part of the channel. These trench diggers are also used for making cunettes along railroads and for other earthmoving work. All elements of the channel are finished in one pass. The productivity of the combined trench digger depends on the working elements used and on the number of passes. One of the basic characteristics of trench diggers is the small pressure per unit of area on the ground (for heavy-duty trench diggers the average value should not be more than 9 meganewtons per sq m [0.9 kilogram-force per sq cm], an especially important feature for working on very moist, soft, and loose ground.

Trench diggers are used extensively in the national economy for working peat deposits, building drainage and irrigation channels, and performing other earth-moving jobs.