Research And Design Gravel Piles Composite Foundation On Tongping Expressway

During“The Eleventh Five-Year”period, China’s economic development mainlydepends on investment, consumption and export among which the investment onhighway construction accounts for a considerable proportion in its whole investmentmeeting the national industrial policy during“The Eleventh Five-Year”. Highwayconstruction needs to meet the requirements of quickness, comfort and safety. In theaspect of speed, we should try to short the distance between the two places in lineselection, which inevitably involves some areas of complex geological conditions. Inthe aspects of comfort and safety, to deal with the complex geology can help thehighway running smoothly and improve the traffic safety. China has a vast territory,with complicated geological conditions and varied soil properties, including a widerange of soft soil and other poor foundation. Improper handling of poor foundationwill directly affect its carrying capacity，which will lead to uneven settlement of thehighway and larger settlement deformation.lots of soft soil in Hunan, Hubei,Guangdong provinces, a research on gravel piles is very imperative.On the basis of the previous research on the gravel piles, we will discuss in thispaper the treatment of soft soil of Tongping expressway and will focus on severaltopics such as the pile design and construction, bearing capacity testing, observationsof subgrade settlement and analysis of finite element. The main contents are asfollowings: 1. The pile length, pile diameter and pile spacing will be designedaccording to the actual circumstances of each section; 2. To test the reinforcementeffect of the pile by the field test，we judge the bearing capacity of single pile by usingheavy typeⅡpower penetration，and use load testing to determine the pile andfoundation bearing capacity 3. With an observation of subgrade settlement and withthe use of FLAC-3D software, we proceed to simulate the subgrade settlement, andconduct an optimization design for the gravel piles. and calculate pile length、pilediameter、pile spacing according to code requirement。...