线路勘测设计(测验必备)(国外英文资料).docVIP

线路勘测设计(考试必备)(国外英文资料) Transportation means: railways, roads, water transportation, aviation, pipelines. National highway network planning by adopting the combination of vertical and horizontal layout, formed by the central cities to radiation and cross even things outside of the north-south thoroughfare, radiation, capital of freeways are 7 9 north-south longitudinal and 18 of lateral line, referred to as the 7918 net overall size is about 85000 kilometers. The planning of the service object to expand further to all people in the city, more than 200000 national 4 a level tourist scenic cities above, all for the highway planning technology level. Highway classification: highway; First class road; Two, three, four roads, Urban road classification: fast road; Arterial road. One; Branch. (1) design vehicle: refers to the vehicle used by road design. (2) the design speed, is also called the calculation speed, is refers to the climate condition good traffic density is small, the car run is only affected by itself, road conditions, driving medium technicians to keep safety, comfortable driving maximum speed. 5. Road boundaries: road clearance is in order to ensure the normal traffic of vehicles and pedestrians, the rules of the road within the scope of a certain height are not allowed to have any facilities and obstacles into space. The road building limit is also known as net empty, consisting of a high net and a net width. Clear height refers to the roads within the scope of the cross section to ensure safe passage must meet the vertical height, clear height of car loading height, height of security should be considered and determine factors such as pavement. The plane design Plane linear three elements: lines; Circular curve; Easement curve. The maximum length of a line: about 20V is acceptable in towns and their vicinity or other landscape, and it is best to control them within 20V Linear minimum length: the minimum length of the same direction curve is no less than si