Study On A Simplified Calculating Method Of Soft Ground Settlement Can Consider The Lateral Deformation

Because of the big deformation of soft soil, computing its settlement is still a problem. Even though the FEM and complex constitutive models are used, the deformation is still hard to determine. In practical engineering, to computing the settlement of soft soil, civil engineers usually combine the deformation modulus of one dimensional stress state with the layer-wise summation method. But this way cannot reflect the strain-stress relations of in-situ stress state, so civil engineers often multiply the result by an empirical coefficient 1.1¹.7 to modify the calculation error. With the development of engineering technology, more and more accuracy of settlement calculation is required. So the traditional method is not suitable, that a new convenient and high accuracy’s calculation method is needed.The main reason that influence the settlement calculation accuracy of the soft soil is that the calculation model of one dimensional stress state does not take the settlement caused by lateral deformation into consideration. For that, this paper puts forward a calculation method which is suitable for three-dimensional deformation. In this method, the settlement of foundation is divided into two part, include Sc—one dimensional consolidation settlement, Sd—settlement caused by shear deformation. Among this two part, Sc can be determined by layer-wise summation method using the parameter of e- p curve and Sd can adopt the same way but the parameter using secant modulus Ep.Another reason that influence the calculation accuracy is the discreteness of e- p curve. But the two important parameter e₀—initial void ratio and E_s1-2（compression modulus corresponding to 100 kPa and 200kPa） are relative accuracy. So,this paper builds a relationship about e₀, E_s1-2 and Cc—compression index, that the relation with e- lgp line is builded. Because the e- lgp line is a straight line, so the parameters are easy to determined, like the Es—compression modulus, in different stress lever. Using these parameters, the consolidation settlement and shear deformation settlement can be determined. The calculation method offered in this paper can both keep the accuracy of computing and comply with the principle of usability. Mainly lad in two aspects: 1) using relevantly easy and reliable way to get parameter, that only need strength parameters-c, φ and deformation parameters-e₀, E_s1-2. This way avoid the error caused by the uncertainly of the parameters of the complex constitutive models. 2) Based on the traditional 1-D consolidation theory, this paper takes in the settlement caused by the shear deformation. The theory is relatively complete.Otherwise, a soft soil settlement calculation was develope for improving the calculation accuracy and efficence.