基于分形理论和Mori-Tanaka方法的颗粒土渗透注浆加固体性能预测方法及应用  

PROPERTY PREDICTION METHODS OF GRANULAR SOIL PENETRATION GROUTING REINFORCED BODY BASED ON FRACTAL THEORY AND MORITANAKA METHOD

作　　者：彭鹏[1] 彭峰 孙振宇[1] 张顶立[1] Peng Peng;Peng Feng;Sun Zhenyu;Zhang Dingli(Key Laboratory for Urban Underground Engineering of Ministry of Education,Beijing Jiaotong University,Beijing 100044,China;Beijing Ruiwei Railway Engineering Technology Co.,Ltd.,Beijing 100038,China)

机构地区：[1]北京交通大学城市地下工程教育部重点实验室,北京100044 [2]北京瑞威铁道工程技术有限公司,北京100038

出　　处：《力学学报》2022年第11期3099-3112,共14页Chinese Journal of Theoretical and Applied Mechanics

基　　金：国家自然科学基金资助项目(51738002,52208382)。

摘　　要：在注浆加固工程中,为了避免空间变异性导致的支护结构受力过大而失稳,提出合理的注浆加固体刚度及强度预测方法十分必要.本文利用分形理论描述颗粒土类型的隧道围岩的孔隙特征,基于迂曲度经验公式建立了地层体孔隙率和面孔隙率的转换关系.以体孔隙率为变量,结合Mori-Tanaka方法,提出新的注浆加固体的宏观刚度预测方法.利用能量法求解连通孔隙不同屈曲半波分布形态下的临界载荷作为加固体的单轴抗压强度,从而建立了新的注浆加固体的强度预测理论模型.以玉京山隧道为工程算例,将本文方法在FLAC3D中进行二次开发,通过对不同的地层单元随机生成孔隙率,并利用本文方法计算并赋予地层单元不同的物理力学性质,实现了围岩空间变异性的模拟,数值模拟和现场监测得到的隧道洞身水平收敛的最大绝对误差仅为8 mm.数值模拟结果表明,对玉京山隧道回填区域进行注浆加固可以降低50%~90%的围岩位移,极大地降低围岩不良区域对应的支护结构弯矩,降低支护结构扭矩至0,并将支护结构变形控制在10 mm以内,但注浆加固难以改变灰岩和回填体之间的载荷分配规律.In the grouting reinforcement project, in order to avoid the instability of the support structure due to excessive force caused by spatial variability, a reasonable prediction method for the stiffness and strength of grouting reinforced body is necessary. The fractal theory is used to describe the pore characteristics of the granular soil type tunnel surrounding rock, and the conversion relationship between the body porosity and surface porosity of the surrounding rock is established based on the empirical formula of tortuosity. A new macroscopic stiffness prediction method for grouting reinforced body is proposed based on the Mori-Tanaka method with the body porosity as the variable. By using energy method to solve the bulking critical load of different half-wave distribution patterns of connecting pores as the uniaxial compressive strength of the grouting reinforced body, so that a new theoretical model for strength prediction of grouted reinforced body is established. The Yujingshan tunnel is used as the engineering background, the method proposed by this paper is secondly developed in FLAC3D, by randomly generating porosity for different surrounding rock elements,the mechanical properties calculated by proposed stiffness and strength prediction methods of grouting reinforced body is assigned to the surrounding rock elements, and the spatial variability of surrounding rock is realized. The maximum absolute error of the horizontal convergence of the tunnel between simulation and monitoring result is only 8 mm. The numerical simulation results show that the grouting reinforcement of the backfill region of Yujingshan tunnel can reduce the surrounding rock displacement by 50%-90%, greatly reduce the bending moment of support structure corresponding to surrounding rock region which has poorly physical and mechanical properties, reduce the support structure torque to 0,and control the support deformation within 10 mm. However, the load distribution law between the backfill region and limestone cannot be changed by g

关 键 词：分形多孔介质 MORI-TANAKA方法 渗透注浆 性能预测 

分 类 号：TU43[建筑科学—岩土工程]