为更好地分析盾构结泥饼风险及渣土塑流性特征，开展旋转剪切试验、三轴试验和坍落度试验，探究长春中风化泥岩渣土黏附强度和抗剪强度特征；基于渣土强度提出长春泥岩渣土合理改良坍落度的建议，并结合实际工程验证其合理性。主要结论如下： 1)随着含水率的增大，长春中风化泥岩渣土（界面）黏聚力先增大后减小，（界面）摩擦角逐渐减小。当含水率为22.58%~27.36%时，土-金属间的界面黏聚力大于黏聚力; 当含水率为15.99%~24%时，界面摩擦角大于内摩擦角。2)渣土坍落度与强度密切相关，随着坍落度的增大，渣土黏附强度和抗剪强度快速降低。当坍落度大于4 cm时，黏附强度和抗剪强度变化较小；当坍落度为0.5~1 cm时，渣土黏附强度大于抗剪强度，因此建议盾构渣土坍落度不小于1 cm，且尽可能使渣土坍落度大于4 cm，以充分减小渣土强度和增大渣土塑流性。
To comprehensively analyze
the muck cake risk of shield tunneling and plastic flow characteristics of
muck, a series of tests on rotational shear, triaxial, and slump are conducted
to explore the adhesion characteristics and shear strength parameters of moderately-weathered mudstone in Changchun, China. Based on muck strength,
reasonable improvements for the slump of the mudstone are proposed, and their
rationality is validated in actual engineering. The main conclusions drawn
include the following: (1) With the increase in the water content, the
(interfacial adhesion) cohesion of the moderately-weathered
mudstone increases first and then decreases, and the (interfacial) friction
angle gradually decreases. At the water content of 22.58%－27.36%, soil and metal exhibit a greater interfacial adhesion than
cohesion. Moreover, when the water content is 15.99%－24%,
the interfacial friction angle is greater than the internal friction angle. (2)
The slump value is closely related to muck strength. With the increase in the
slump value, the adhesion and shear strengths of the muck exhibit a rapid
decrease. When the slump value is greater than 4 cm, adhesion and shear
strengths show relatively small changes. In addition, at the slump value
between 0.5 and 1 cm, the muck attains a greater adhesion strength than shear
strength. Therefore, the slump value of moderately-weathered
mudstone during shield tunneling should not be less than 1 cm, and that of muck
should be as large as possible that is, more than 4 cm, to reduce the muck′s strength and increase its fluidity sufficiently.
