深厚冲积层高强钢筋混凝土井壁力学特性研究

 通过实验和理论计算，对在均匀荷载作用下高强钢筋混凝土井壁的力学特性进行分析。实验结果表明：高强钢筋混凝土井壁具有很高的承载力，影响其承载力的主要因素依次为混凝土的强度等级、厚径比和配筋率；在均匀外荷载作用下，混凝土强度提高10 MPa，井壁的极限承载力提高4 MPa左右，配筋率对井壁的极限承载力影响很小；高强钢筋混凝土井壁结构破裂时，环向钢筋沿破坏面发生塑性弯曲，混凝土破坏面与最大主应力方向的夹角为25°～30°，属压剪破坏。理论分析时，采用线性软化本构模型以及符合混凝土强度特性的Mohr-Coulomb强度准则，推导出高强钢筋混凝土井壁极限承载力的理论计算公式，并且其计算结果得到实验验证。

RESEARCH ON MECHANICAL CHARACTERISTICS OF HIGH-STRENGTH REINFORCED CONCRETE SHAFT LINING IN DEEP ALLUVIUM

The alluvium traversed by shaft in mine becomes thicker and thicker along with the development of deeper mine construction. The high-strength reinforced concrete shaft lining is adopted in deep alluvium. For high-strength reinforced concrete shaft lining，its mechanical characteristics are analyzed by experiment and theory. The experimental results show that the ultimate bearing capacity of the high-strength reinforced concrete shaft lining is much great. The factors that influence the ultimate bearing capacity of the high-strength reinforced concrete shaft lining are，in turn，the strength grade of concrete，the ratio of thickness to radius and the ratio of reinforcement. Under the condition of uniformly loading，when the strength of concrete increases 10 MPa，the ultimate bearing capacity of shaft lining increases 4 MPa. However，the effect of the ratio of reinforcement on the ultimate bearing capacity of shaft lining is very small. When the shaft lining comes to failure，there is an inclined crack in the high-strength reinforced concrete shaft lining，and the circumferential reinforced steel bars bend at the inclined crack. The failure of high-strength reinforced concrete shaft lining is compression-shear mode，and the angles between the failure plane of concrete and the direction of the maximum principal stress are 25°–30°. Using the linear softening constitutive model and Mohr-Coulomb strength criterion，the theoretical formula of ultimate bearing capacity is deduced for the high-strength reinforced concrete shaft lining. The results obtained by formula agree well with the experimental data.