The safety monitoring for earth rock dam consists of two parts. One is the monitoring of stress which is mainly about pore water pressure monitoring. The other is about deformation monitoring including observation of surface subsidence, deep layer ground subsidence and horizontal displacement on the abutment of the dam. The actual project shows that the water pressure and the horizontal displacement on the abutment of the dam will be significantly larger than normal status before the dam is in danger. It can give early warning with combination of the results of surface subsidence and deep displacement monitoring. In order to research the whole deformation of the dam and settlement of the soft foundation, the parameters of Duncan-Chang model for undisturbed soil are gained by using triaxial compression test, and the subroutine of the Duncan-Chang nonlinear constitutive model is embedded into the ABAQUS based on the secondary development platform of ABAQUS effectively. Using the ABAQUS finite element software the stress-deformation and the construction areas of the dam in each grading loading are simulated. The comparison between monitoring and simulating results shows that the model can present the trends of the dam deformation well. Calibrating model parameters with the parameters of observation, the trend of dam deformation could be reflected more accurately and give real-time monitoring.%土石坝的安全监测包括两个部分,一是关于应力的监测,主要是孔隙水压力的监测；二是变形的监测,包括地表沉降、地基深层分层沉降、坝肩水平位移等.实际工程表明,土石坝在填筑施工中出现安全问题时,超孔隙水压力与坝肩水平位移会明显偏大,结合地表沉降与坝基深层位移监测结果能够对坝体施工安全有效预警.为研究土石坝坝体与软弱地基的沉降、变形规律,取现场原状土样进行室内三轴压缩试验,得到了原状土样的Duncan-Chang模型参数；基于ABAQUS二次开发平台将Duncan-Chang非线性本构模型子程序有效的嵌入其中.通过ABAQUS有限元模拟分析了在各级荷载作用下坝体的应力与变形和破坏区域,通过与监测结果进行比对,显示模型能够较好的反映土石坝的变形趋势.用观测值校准模型参数后,能更准确的反映坝体变形走势,实现实时监控
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