The Application Research On The Technology Of Soft Ground Improvement

With the rapid development of economy in China and improvementof geotechnical engineering technology, it is possible for the settlementand deformation of railway subgrad to be controlled to meet the strictoperating requirements of high speed, safety and comfort of high speedrailway. This paper introduces the subgrade requirements for highspeed railway, the classification and characteristics of soft soil, theusual methods of soft ground improvement. By taking the groundtreatment of Qinghuangdao-Shenyang passenger railway as an example,the geological condition of soft ground, ground treatment design,construction quality tests and bearing capacity tests, research of softground treatment based on the test results are presented.The key of subgrade treatment is to control the settlement of thebearing stratum. Effective measures should be taken for the unqualifiedsoft subgrade to meet the post-construction requirements.The settlement and statibility of natural ground under the design loadto be exerted is calculated.Then based on that, the possible groundtreatment motheds are considered. The appropriate ground treatmentmotheds were adopted after the the settlement, siliding stability andeconomic with regard to the possible methods being compared.Based on the analysis of the distribution of soft foundation and itsgeological condition along the line, and test results, measures of naturalfoundation, replacement, dry method of DMM, high pressure jetgrouting, deep mixing method, sand pile, stone column, sand drain,plastic draining plate and geosythetics reinforced soil are adoptedrespectively. Before the final adoption of these methods, a experimentalground is selected to apply these method and the treatment result istested. This presents the necessary parameters for the design of groundtreatment of the whole line. Settlement gauges and inclinometers wereused to measure the settlement and horizontal displacement of treatedground. The field measured results are analyzed to optimize thesubsequent design and construction.Through the research of the observation results, comparison, analysisand evaluation of the effect with regard to the stability, settlement anddeformation, post-construction settlement rate of different groundtreatment measures on different soft ground are carried. This makes itpossible to adopt the dynamic design, which means that the design canbe improved according to the field measured data.