超大直径泥水盾构土岩交互地层掘进载荷计算与分析

Load Calculation and Analysis of Super-Large-Diameter Slurry Shield Tunneling in Soil-Rock Interbedded Strata

为解决土岩交互地层超大直径泥水盾构推力、转矩参数设计取值与施工参数控制问题,提出土岩交互地层掘进载荷计算模型。根据泥水盾构特点分析载荷各分项组成,建立掘进载荷数学模型,基于土岩交互地层模型、刀盘几何模型对载荷计算模型进行数值仿真,利用汕头苏埃通道基岩段施工数据对模型进行计算验证,分析基岩侵入高度、岩石强度、贯入度等影响因素对刀盘转矩的影响规律。计算分析结果表明:1)掘进载荷计算模型理论推力与实测值误差为-6.4%~5.6%,刀盘理论转矩与实测值误差为-9.5%~9.0%,模型具有较高的精度,可满足装备设计和工程应用的实际需要;2)随基岩侵入高度和贯入度增加,推力、转矩均增加,但转矩对岩石侵入高度、贯入度变化更灵敏;3)岩石单轴抗压强度每增加10 MPa,转矩约上升7%(强度在50~100 MPa,贯入度5 mm/r);4)在高贯入度下,刀盘转矩随岩石侵入高度的增加效应越显著;5)在刀盘1/2位置附近,岩石高度增量引起的转矩增加最为显著。建议在施工中根据地勘确定的基岩侵入高度、岩石强度、贯入度参数计算出对应的转矩,可作为施工中掘进控制参数。

A computational model of tunneling load in soil-rock interbedded strata is devised to sufficiently design the thrust and torque parameters and efficiently regulate the construction parameters of super-large-diameter slurry shield.According to the characteristics of the slurry shield,the load components are analyzed and a mathematical model of tunneling load is established.Next,the load computational model is numerically simulated using the soil-rock interbedded strata model and the cutterhead geometry model.Finally,the model is validated using construction data from the bedrock region of the Su′ai tunnel in Shantou,China,and the influence rules of factors such as bedrock invasion height,rock strength,and penetration degree on cutterhead torque are examined.The results indicate the following:(1)The error between theoretical thrust by the model and the measured value is-6.4%~5.6%and the error between theoretical torque of cutterhead and the measured value is-9.5%~9.0%,demonstrating the high precision of the model and the ability to meet the actual needs of equipment design and engineering application.(2)The thrust and torque rise with an increase in bedrock intrusion height and penetration degree,where the torque is more sensitive to the change of rock intrusion height and penetration degree.(3)The torque increases by approximately 7%(the strength is 50~100MPa and the penetration degree is 5 mm/r)as the uniaxial compressive strength of rock increases every 10 MPa.(4)When the penetration degree is high,the rising amplitude of cutterhead torque increases drastically as the rock intrusion height grows.(5)The torque increase caused by rock height increment near the cutterhead 1/2 position is the most substantial.The equivalent torque estimated based on bedrock intrusion height,rock invasion strength,and penetration parameters discovered during construction by geological prospecting can be regarded as the driving control parameters in construction.