Analysis Of Critical Height Of Embankment During Construction On Q₄～m-Q₄～(al) Soft-Soil Layer In North Of Jiangsu

In this thesis, based on the systematic summary of existing research home and abroad, a significant problem related to critical height of embankment during the construction of highway engineering have been discussed and researched systemically in theory and practice from four aspects:(1) Research of influence of the critical height to the deformation and stability of the soft ground during the construction.Based on the settlement data observed in fenguan Xuzhou-Lianyungang highway and lateral displacement and pore pressure data on other published case -histories.the influence of the critical height to the deformation and stability of the soft ground during the construction have been researched in detail by analyzing the H - S -T curve S - H curve lateral displacement curve Ym-S curve △u-γ H curve ,whichcontain three aspects such as settlement lateral displacement and pore pressure.(2) Research of the form mechanism of the critical height.The form mechanism of the critical height have been discussed and researched in theory from three aspects by analyzing the Luanyungang soil's physical and mechanical behaviors, the existing of the critical height is the function of the effect of crusts soil's overconslidation and soil's structure in fenguan Xuzhou-Lianyungang highway.(3) Research of influence factor to the value of the critical height of embankment.All of influence factors of the critical height and their relation were also discussed stemically, the geometry of embankment fill material of embankment construction rate the soft ground and treatment all affect the value of the critical height. Some measures related to The design geometry of the embankment such as reverse press and delying slope are beneficial to improve the critical height as the same an treatment of the soft ground, the liner regress model with many element was used to summarize the relation between the critical height and the thickness of soft clay and crust layer. Then the experiential regress equation was shown..(4) Research of the methods to estimate the value of the critical height.The critical height generated during the construction can be estimated in different methods such as following: 1. by analyzing the measured data 2.computed by theoretical formula 3. by means of centre test model. Research fruits related to three methods have also been summarized .Based on the reliable conclusions proposed by Tavenas and Leroueil , the author bring forward a new thought and develop a simple theoretical formula to estimate the critical height ,which consider the effect of the crust, the result computered by the author was compared to the others thoughly.