以驷马山中弱膨胀土为研究对象，以水泥作为改性材料，通过室内常规三轴试验，研究水泥改性膨胀土的强度与变形特性。试验结果表明：掺入水泥后，能提高膨胀土的塑限，降低塑限指数和自由膨胀率；水泥改性膨胀土三轴应力应变曲线存在弹性、非线性强化、应力软化等三个阶段，并随围压的增大，由软化型逐渐向硬化型发展；峰值强度、残余强度均随围压的增大而增大，试样为剪切破坏形态，剪切破坏角符合摩尔-库伦理论计算值。

The conventional laboratory triaxial tests are carried out to study strength and deformation characteristics of cement-modified expansive soil by taking medium/weak expansive soil in Simashan as object of the study and cement as modified material.The results show that the plastic limit of expansive soil can be increased and the plastic limit index and free expansion rate can be reduced by cement modification.The triaxial stressstrain curve of cement-modified expansive soil presents three segments of elasticity,non-linear strengthening and stress softening.With the increase in confining pressure,the softening type gradually develops to hardening type.Both peak strength and residual strength increase with the increase in confining pressure.The specimens are in shear failure mode,and the shear failure angle conforms to the calculated value of MohrCoulomb theory.