residual soil underlying engineering properties of soil， and the bad by geography and climate change affects， and because of all the technical level， economic conditions and the construction of the reasons of the mechanical equipment， China's railway roadbed design usually adopts low technical standard， the construction quality often lax， leading to various requirements of railway and become a bed disease wide distribution， management difficult， multiple strong disease， and in recent years with the speed of the train and heavy of subgrade stress level， Distribution condition and functions of the significant Beca
