基于K?tter方程的盾构掘进面上被切削土体受力研究
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摘要
为了计算不同土体性质与不同掘进参数下盾构刮刀与土体之间的作用力以及由此带来的切削扭矩,引入了修正后的K?tter方程作为补充方程,求解出开挖面上土体在被动切削至破坏时滑动面上的应力分布,建立了被切削土体受力模型,求解出刮刀刃面与土体之间的正压力P、摩擦力Q与侧向土体间抗剪阻力U,进而推导出刀盘切削扭矩T的计算公式。分析得到特定刀盘上刮刀的P, Q,U值随土体c,j值增大而增大,通过适当提高刮刀刃面粗糙度来增大摩擦可使土体更易被切至破坏; P, Q,U值随刀盘转速w增大而减小, P, Q随支护荷载p线性增大且p对于被切削土体受力的影响在砂性土中较大,最终给出特定刀盘掘进至部分种类土体中的切削扭矩值作为工程参考。
To calculate the forces between shield scraper and soils as well as the cutting torque caused by them with different tunneling parameters in different soils, a modified K?tter equation is introduced as a supplement to solve the stress distribution on the sliding face when the soils in excavation face are being passively cut to a damage state. A mechanical model for cutting soils is established, and the pressure and friction between the soils and the surface of shield scraper and the lateral shear resistance are solved. Then the method for calculating the cutting torque of cutter head is derived. It can be acquired that the pressure, friction and lateral shear resistance increase with the cohesive force and internal friction angle and decrease with the rotation rate, which illustrates that a properly coarser scraper surface makes the soils easier to be cut, and a lower rotation rate can reduce the force of the tools. The pressure and friction increase linearly with the shield support pressure, which is more obvious in sand. Some cutting torques in different soil types are given as engineering references ultimately.
To calculate the forces between shield scraper and soils as well as the cutting torque caused by them with different tunneling parameters in different soils, a modified K?tter equation is introduced as a supplement to solve the stress distribution on the sliding face when the soils in excavation face are being passively cut to a damage state. A mechanical model for cutting soils is established, and the pressure and friction between the soils and the surface of shield scraper and the lateral shear resistance are solved. Then the method for calculating the cutting torque of cutter head is derived. It can be acquired that the pressure, friction and lateral shear resistance increase with the cohesive force and internal friction angle and decrease with the rotation rate, which illustrates that a properly coarser scraper surface makes the soils easier to be cut, and a lower rotation rate can reduce the force of the tools. The pressure and friction increase linearly with the shield support pressure, which is more obvious in sand. Some cutting torques in different soil types are given as engineering references ultimately.
引文
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[2]徐前卫,朱合华,丁文其,等.均质地层中土压平衡盾构施工刀盘切削扭矩分析[J].岩土工程学报,2010,32(1):47-54.(XU Qian-wei,ZHU He-hua,DING Wen-qi,et al.Cutting torque during tunnelling process of earth pressure balance shield machine in homogeneous ground[J].Chinese Journal of Geotechnical Engineering,2010,32(1):47-54.(in Chinese))
[3]HE Chuan,WANG Bo.Research progress and development trends of highway tunnels in China[J].Journal of Modern Transportation,2013,21(4):209-223.
[4]徐小荷,余静.岩石破碎学[M].北京:煤炭工业出版社,1984.(XU Xiao-he,YU Jing.Rock fragmentation[M].Beijing:China Coal Industry Publishing House,1984.(in Chinese))
[5]EVANS I.The force required to cut coal with blunt wedges[J].International Journal of Rock Mechanics&Mining Sciences&Geomechanics Abstracts,1965,2(1):1-12.
[6]NISHIMATSU Y.The mechanics of rock cutting[J].International Journal of Rock Mechanics&Mining Sciences&Geomechanics Abstracts,1972,9(2):261-270.
[7]暨智勇.盾构掘进机切刀切削软岩和土壤受力模型研究及实验验证[D].长沙:中南大学,2009.(JI Zhi-yong.Research and experimental verification of stress model of cutting machine cutting soft rock and soil by shield tunnelling machine[D].Changsha:Central South University,2009.(in Chinese))
[8]崔国华,王国强,王继新,等.全断面盾构掘进机切削刀具的计算力学模型求解[J].吉林大学学报(工学版),2008,38(增刊2):144-148.(CUI Guo-hua,WANG Guo-qiang,WANG Ji-xin,et al.Cutting dynamic model for cutters of shield machine under soft soil[J].Journal of Jilin University Engineering and Technology Edition,2008,38(S2):144-148.(in Chinese))
[9]TERZAGHI K.Theoretical soil mechanics[M].New York:John Wiley and Sons,Inc,1943.
[10]KoTTER F.Die bestimmung des drucks an gekrümmten gleitfl?chen,eine aufgabe aus der lehre vom erddruck[J].Sitzung Der Physikalisch-Mathematischen Classe Vom,1903:229-233.
[11]孔德顺.K?tter方程在挡土墙被动土压力求解中的应用[D].南京:河海大学,2008.(KONG De-shun.Application of K?tter equation to solving passive earth pressure of retaining wall[D].Nanjing:Hohai University,2008.(in Chinese))
[12]余志刚.泥质粉砂岩地层泥水盾构掘进参数变化规律及关联性分析[J].施工技术,2018,47(1):116-121.(YUZhi-gang.Change rule and correlation analysis of slurry shield tunneling parameters under argillaceous siltstone formation[J].Construction Technology,2018,47(1):116-121.(in Chinese))