多层地基条件下的一维沉降计算一般采用分层总和法。以应力面积计算法为例，

The calculation of one-dimensional settlement under multi-layer foundation generally adopts the layered sum method. <br>Taking the stress area calculation method as an example, there are n layers of foundation soil distributed in the range of the compression layer, the compression modulus values ​​are Es1, Es2, Esn, and the depth of the bottom of the layer is z1, z2, zn, respectively. The expression of soil compression Si can be written as: <br>where z is the additional stress on the i-layer foundation soil, Ai is the distribution area of ​​the additional stress in the i-layer range, Ai = phi, where p is a large area Pressure, hi is the thickness of layered soil. <br>Therefore, the calculation formula of the total settlement of the n-layer foundation soil can be expressed as:

The one-dimensional settlement calculation under multi-layer foundation conditions is generally calculated by hierarchical sum.<br>In the case of stress area calculation, where the compression layer is distributed within the compression layer, there are n-layer ground soils with compression modulus values of Es1, Es2, Esn, and the depth of the layer is z1, z2, and zn, the expression of the compression volume of the i-layer soil can be written as:<br>The layer z is the additional stress on the i-layer foundation soil, the Ai is the distribution surface of the additional stress in the i-layer range, and the Ai-p?hi, where p is the large area pressure and the hi is the layered soil thickness.<br>Thus, the calculation of the total settling amount of the n-layer ground soil can be expressed as:

Generally, the method of layered summation is used to calculate the one-dimensional settlement of multi-layer foundation.<br>Taking the calculation method of stress area as an example, there are n layers of foundation soil distributed in the range of compression layer, and their compression modulus values are Es1, ES2,  ESN, and the bottom depth of layer is Z1, Z2,  Zn, respectively. Then the expression of compression amount △ Si of layer I soil can be written as follows:<br>Where, Z is the additional stress borne by the foundation soil of layer I, AI is the distribution area of the additional stress within the range of layer I, AI = P  Hi, where p is the large area pressure and hi is the thickness of layered soil.<br>Therefore, the total settlement of n-layer foundation soil can be expressed as: