轴压水压下井壁混凝土强度准则与承载力研究

Research on strength criterion and bearing capacity of shaft lining concrete under axial pressure and hydraulic pressure

为解决含水基岩段井壁结构设计安全性问题,基于相似模型理论,将混凝土强度等级、厚径比、配筋率作为井壁承载力的影响因素,设计并完成9组模型试验。采用轴压水压逐级加载方式,研究相应条件下井壁混凝土应力应变特性、破坏特征与机制,建立井壁混凝土强度准则及其结构承载力计算公式。结果表明：井壁大致呈压剪破坏状态,井壁混凝土应力内侧大外侧小;获得的强度准则与现行矿井设计准则相比验算精度更高,偏差范围为-6. 00%～6. 94%;随着混凝土强度等级提高,井壁承载力呈线性增加趋势,平均每提高10 MPa,承载力增加11. 04%,而提高配筋率对井壁承载力影响极其微弱,且不利于控制造价。

To solve the safety problem of shaft lining design in water-bearing bedrock segment,based on the similarity model theory,concrete strength grade,thickness diameter ratio and reinforcement ratio were taken as the influencing factors on the bearing capacity of shaft lining,and nine sets of orthogonal tests were designed and completed. Stress and strain characteristics,failure characteristics and mechanism of shaft lining concrete under corresponding conditions were studied. A strength criterion and bearing capacity calculation formula of shaft lining concrete were established. The model generally shows compressive shear failure and stress on the inside of shaft is greater than that on the outside,that compared with the present mine design formula,the strength criterion has higher accuracy,and the deviation range is-6. 00% to6. 94%,that as the concrete strength grade increases,the bearing capacity of shaft lining increases linearly,an increase of 10 MPa causes an average increase of 11. 04%,that increasing the reinforcement ratio has a very weak influence on the bearing capacity of shaft lining,and is not conducive to controlling the cost.