Digging Trenches Is One Of The Oldest Types Of Workwith Both Construction And Excavating. Prior To WorldWar 2, Trenches Were Dug By Hand. As Workers Dug Thetrenches Deeper, The Sides Needed To Be Shored Orsupported, To Keep The Walls Of The Trench From Cavingin. Following The World War, Several Innovations Were Madein Backhoes, And Trench Digging Seemed To Fade Awayas A Profession. By 1950, Hydraulically Actuatedbackhoes Were Developed, Which Make It Possible To Rapidly Dig Very Deep Trenches. Resulting From Theinnovations With Backhoes, And Because There Were Noworkers Inside Digging The Trenches, The Walls Nolonger Needed To Be Shored.All Types Of Trenches Have What's Known As A Stand Uptime. This Time Is The Amount Of Time That Elapsesfrom The Time The Ditch Is Dug Until The Time Thetrench Walls Start To Collapse. The Stand Up Timeis Dependant On Many Factors, Which Include The Typeof Soil, Water Content, Trench Depth, Weatherconditions, And Whether Or Not The Soil Has Beendisturbed. The Stand Up Time Can Be As Short As Zero Seconds Or As Long As Several Months, As They Are Verydifficult To Predict. Before The Trench Can Be Dug,someone Must Take Soil Samples As Way Of Estimatingthe Stand Up Time. Keep In Mind That The Soilconditions Can Be Dramatically Different Only A Few Feet From Where The Sample Of The Soil Was Taken.After The Trench Has Been Dug, Workers Will Go Downinto The Trench, And Perform Whatever Work Is Needed, Such As Laying Pipe Or Installing Telephonelines, Welding Pipe, Or Installing Valves. If Thetrench Walls Aren't Supported, There Is The Possibilityof The Walls Collapsing And Trapping The Workers Inthe Trench. Throughout History, There Have Been100 - 300 People Killed In The U.S. Each Yeardue To Trenches Collapsing.The Public Has Become Very Aware That Industrialprogress Will Often Have Negative Side Effects Aswell. The Place Of Engineers Protecting The Public From These Types Of Side Effects Is A Verycontroversial Issue. The Use Of Trench Boxes Onthe Site, Will Help To Ease This Debate.The Trench Box, Also Called A Trench Shield, Maybe Placed In The Trench To Prevent Failures Frominjuring Workers. The Trench Box Consists Of Two Large Plates, Normally Made From Steel, Which Areparallel To The Walls Of The Trench, And Horizontalcross Members Which Will Hold The Two Platesapart.The Lower Edge Of The Trench Box Rests At Thebottom Of The Trench, With The Top Edge Of The Box Extending Above The Top Of The Trench. Theworkers Will Stay Between The Plates Of The Trenchbox, So That If The Trench Does Collapse, The Dirtwill Be Stopped By The Outside Of The Trench Box. As The Work Progresses, The Trench Box Is Pulledalong In The Trench With A Backhoe Or Other Machine.When A Project Calls For A Large Excavation Suchas Digging The Foundation For A Tall Building, Thesupporting Structure For The Excavated Walls Willbe Specified In The Plans. The Big Problem Withnot Using Trench Boxes Occurs In Cities, When Water Or Sewer Lines Are Being Installed Orrepaired. The Engineer Doesn't Specify For Thetrench Box In The Plans, But Instead Leaves Itup To The Contractor.Anytime You Are Going To Be Digging Trenches Orworking In Them, You Should Always Use Common Senseand Take Your Time. Trenches Can Be Very Deadly,especially If Trench Boxes Aren't Used. To Be Onthe Safe Side, You Should Always Use A Trench Boxif You Need To Be In The Trench. If You Don'tneed To Be In The Trench - Do The Smart Thingand Let The Machines Do All Of The Work.PPPPP(word Count 639)
