Abstract：Based on in-situ plate loading test P-S curve，a new settlement computation of the foundation is proposed. Supposing that the in-situ plate loading test P-S curve is governed by a hyperbola equation，a hyperbola model is constructed，and the tangent modulus and secant modulus of the soil can be obtained from this hyperbola equation，which could be used in the layer-wise summation method to compute the foundation settlements，and to form the hyperbola tangent modulus method and hyperbola secant modulus method for natural soil. Under the assumption of the in-situ plate loading test P-S curve as a hyperbola equation，it only needs three parameters for the method，that is initial tangent modulus Es0，internal friction angle j and cohesion c. For any other in-situ plate loading test P-S curve，the relationship between soil tangent modulus and loading level is constructed；and the general curvilinear tangent modulus method is proposed which is applied to the layer-wise summation method. As the tangent modulus or secant modulus change nonlinearly with the loading level changing，the new method can calculate the settlement when the load approaches to the ultimate bearing capacity of foundation. Based on the undisturbed soil tangent modulus and secant modulus，the new method of the foundation nonlinear settlement is presented，which can be used to calculate the complete process of the nonlinear settlement of the foundation. Because the soil deformation parameters are determined from the in-situ plate loading test，the intactness and nonlinearity for the soil can be better considered；the foundation nonlinear settlement can be calculated more correctly. Moreover，few parameters are needed. The effectiveness and practicability of this new method are examined in the pile foundation，raft foundation，complex embankment foundation and composite foundation. This may be a great progress for settlement computation of soil foundation.
