为了研究软土地区沉井下沉阻力分布特征,以宁波某综合管廊沉井为研究对象,开展了沉井土层土体直剪试验和常规三轴试验,研究表明:该软土的应力-应变关系呈现出典型的硬化型发展,剪切初期应力随着应变的增加较快,且表现出围压越大剪应力越大,当应变20%时试样剪切破坏。沉井在下沉过程中,需要随时做好监测,利用测试数据对下沉过程做了受力分析,对不同深度下沉井刃脚端阻力和井壁侧摩阻力的分布规律进行了研究。最后,基于沉井下沉穿越淤泥土层时σ_f0和下沉深度S 数据规律,拟合出相应的经验公式,测试结果表明,该沉井下沉过程中侧阻力尚未达到极大值,沉井相对两面的侧阻力并不相同,研究成果可供同类工程参考。

In order to study the distribution features of sinking resistance of caisson in soft clay area, taking the open caisson of a comprehensive pipe gallery in Ningbo as the research object, the basic soil experiments of open caisson were carried out. The results show that the basic mechanical parameters of soft soil were obtained through direct shear test and conventional triaxial test; The sinking process of the open caisson is monitored in real time, the stress mechanism of the sinking process of the open caisson is deeply analyzed, and the distribution laws of shaft wall side friction and blade foot end resistance at different depths of the open caisson are obtained. At last, based on the test data, when the open caisson foundation sinks through the silt soil layer is put forward σ_f0 changes with the sinking depth, and the corresponding empirical formula is fitted. The test results show that the lateral resistance of the caisson has not yet reached the maximum value during the sinking process, and the lateral resistance of the caisson relative to the two sides is not the same. The research results can be used to provide a reference for the same kind projects.