爆破冲击荷载下花岗岩残积土的力学响应试验研究
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摘要
地铁隧道盾构施工前,通常需要对风化层中的孤石进行爆破处理,爆破荷载不可避免地对周围土体产生扰动.为了调查爆破冲击荷载对花岗岩残积土力学行为的影响,开展了不同冲击速率、频率、振动峰值应力及有效围压作用下花岗岩残积土的冲击动力试验,分析冲击荷载引起的超静孔隙水压力和变形的发展规律与破坏模式.结果表明:高速冲击引起的颗粒重排会增大土的内摩擦角,但强度增大的同时也会破坏原生结构强度,土体产生更多裂缝;振动峰值应力与频率对残积土的影响均存在着临界值,振动峰值应力与频率超过临界值时,强度软化且变形量增大;低围压下残积土可能会出现剪胀与剪切带破坏;提出的3种爆破冲击破坏类型中,低频高振动峰值应力的冲击条件下易出现严重的冲击破坏,频率3 Hz、振动峰值应力400 kPa是厦门花岗岩残积土介于破坏型与亚稳定型的临界影响值,因此,工程实践中应关注低频、高振动峰值应力的爆破冲击对周围土体带来的危害.研究可为花岗岩风化层中爆破法处理孤石提供施工参数,也可为考虑爆破振动影响的土层的力学参数确定与评价提供技术支持.
Blasting is commonly adopted prior to subway tunnel construction to deal with the boulders in weathered granite formations, which inevitably exercise disturbance on surrounding soils. In order to investigate the influence of blast loading on the mechanical behavior of granite residual soil, a series of dynamic impact tests under various impact rates, frequencies, blast peak stresses and effective confining pressures were carried out. And the development of excess pore water pressure, axial deformation and failure mode were analyzed. The results indicated that the rearrangement of soil particles caused by impact loading will increase effective internal friction angle. However, the original structural strength of soil will be damaged and more cracks emerged at the same time. The critical values for blast peak stress and frequency were suggested. When blast peak stress and frequency exceed the critical value, the strength of soil softens and the deformation increases. Under low confining pressure, dilatancy and shear band failure were observed.Furthermore, three failure modes of granite residual soil under blasting impact loading were proposed. Severe impact damage will be caused under low frequency or high blast peak stress impact conditions. The frequency of 3 Hz and the blast peak stress of 400 k Pa are the critical conditions that determine whether the soil is metastable or seriously destroyed. More attentions should be paid to the hazards caused by blasting impact with the low frequency and high blast peak stress in granite residual soil in Xiamen. This research can provide parameters for the boulder treatment in soil formations disturbed by blasting.
Blasting is commonly adopted prior to subway tunnel construction to deal with the boulders in weathered granite formations, which inevitably exercise disturbance on surrounding soils. In order to investigate the influence of blast loading on the mechanical behavior of granite residual soil, a series of dynamic impact tests under various impact rates, frequencies, blast peak stresses and effective confining pressures were carried out. And the development of excess pore water pressure, axial deformation and failure mode were analyzed. The results indicated that the rearrangement of soil particles caused by impact loading will increase effective internal friction angle. However, the original structural strength of soil will be damaged and more cracks emerged at the same time. The critical values for blast peak stress and frequency were suggested. When blast peak stress and frequency exceed the critical value, the strength of soil softens and the deformation increases. Under low confining pressure, dilatancy and shear band failure were observed.Furthermore, three failure modes of granite residual soil under blasting impact loading were proposed. Severe impact damage will be caused under low frequency or high blast peak stress impact conditions. The frequency of 3 Hz and the blast peak stress of 400 k Pa are the critical conditions that determine whether the soil is metastable or seriously destroyed. More attentions should be paid to the hazards caused by blasting impact with the low frequency and high blast peak stress in granite residual soil in Xiamen. This research can provide parameters for the boulder treatment in soil formations disturbed by blasting.
引文
1张先伟,孔令伟,臧濛.雷州半岛玄武岩残积土的工程地质特性研究.岩土工程学报,2014,36:855-863
2 Zhang X W,Kong L W,Li J J.Influence of dry and wet seasons on disintegration characteristics of basalt residual soil from the Leizhou Peninsula,China.Q J Eng Geol Hydrogeology,2018,51:450-460
3张先伟,李仁耿,郑永民,等.顺德强风化岩层预应力管桩桩端土软化的现场试验研究.中国科学:技术科学,2016,46:975-986
4 Ren D J,Shen S L,Cheng W C,et al.Geological formation and geo-hazards during subway construction in Guangzhou.Environ Earth Sci,2016,75:934
5吴帅峰,余永强,褚怀保,等.孤石爆破对土体扰动规律的试验研究.爆破,2015,32:12-16
6 An J,Tuan C Y,Cheeseman B A,et al.Simulation of soil behavior under blast loading.Int J GeoMech,2011,11:323-334
7 Wang Z,Lu Y.Numerical analysis on dynamic deformation mechanism of soils under blast loading.Soil Dyn Earthquake Eng,2003,23:705-714
8 Tong X,Tuan C Y.Viscoplastic cap model for soils under high strain rate loading.J Geotech Geoenviron Eng,2007,133:206-214
9 Henrych J.The Dynamics of Explosion and its Use.New York:Elsevier,1979
10 Gohl W B,Jeferies M G,Howie J A.Explosive compaction:Design,implementation and effectiveness.Géotechnique,2000,50:657-665
11王明洋,赵跃堂,钱七虎.饱和砂土动力特性及数值方法研究.岩土工程学报,2002,24:723-729
12 Omidvar M,Iskander M,Bless S.Stress-strain behavior of sand at high strain rates.Int J Impact Eng,2012,49:192-213
13林伟弟,李彰明,罗智斌.三轴冲击荷载作用下淤泥力学响应研究.岩土力学,2015,36:1966-1972
14聂庆科,李佩佩,王英辉,等.三轴冲击荷载作用下红黏土力学性状.岩石力学与工程学报,2009,28:1220-1225
15 Zhang X W,Kong L W,Yin S,et al.Engineering geology of basaltic residual soil in Leiqiong,southern China.EngGeol,2017,220:196-207
16 Ng C W W,Yung S Y.Determination of the anisotropic shear stiffness of an unsaturated decomposed soil.Géotechnique,2008,58:23-35
17 ASTM Standard D2487.Standard Practice for Classification of Soils for Engineering Purposes(Unified Soil Classification System).ASTMInternational,West Conshohocken,PA,2006
18 ASTM Standard D5311M-13.Standard Test Methods for Load Controlled Cyclic Triaxial Strength of Soil.ASTM International,West Conshohocken,PA,2013
19 Henkel D J,Gilbert G D.The effect measured of the rubber membrane on the triaxial compression strength of clay samples.Géotechnique,1952,3:20-29
20ХанукаевАН.矿岩爆破物理过程.刘殿中,译.北京:冶金工业出版社,1980
21 Suescun-Florez E,Omidvar M,Iskander M,et al.Review of high strain rate testing of granular soils.Geotech Test J,2015,38:20140267
22 Yang R,Chen J,Yang L,et al.An experimental study of high strain-rate properties of clay under high consolidation stress.Soil Dyn Earthquake Eng,2017,92:46-51
23 Mortezaie A R,Vucetic M.Effect of frequency and vertical stress on cyclic degradation and pore water pressure in clay in the NGI simple shear device.J Geotech Geoenviron Eng,2013,139:1727-1737
24 Felice C W.The response of soils to impulse loads using the split-hopkinson pressure bar technique.Dissertation for the Doctoral Degree.University of Utah,1985
25 Kumar R,Choudhury D,Bhargava K.Prediction of blast-induced vibration parameters for soil sites.Int J Geomech,2013,14:04014007
26 TM 5-855-1.Fundamentals of Protective Design for Conventional Weapons.Department of the Army,Washington,DC,USA,1986
27 Leong E C,Anand S,Cheong H K,et al.Re-examination of peak stress and scaled distance due to ground shock.Int J Impact Eng,2007,34:1487-1499
28 Kong W K.Blasting assessment of slopes and risks planning.AUST J Civil Eng,2012,10:177-192
29 Yoshimi Y,Oh-oka H.Influence of degree of shear stress reversal on the liquefaction potential of saturated sand.SOILS Found,1975,15:27-40
30张建民,王稳祥.振动频率对饱和砂土动力特性的影响.岩土工程学报,1990,12:89-97
31 Matsui T,Ito T,Ohara H.Cyclic stress-strain history and shear characteristics of clay.J Geotech Eng,1980,106:1101-1120
32 Yasuhara K,Yamanouchi T,Hirao K.Cyclic strength and deformation of normally consolidated clay.SOILS Found,1982,22:77-91
33张茹,涂扬举,费文平,等.振动频率对饱和黏性土动力特性的影响.岩土力学,2006,27:699-704
2 Zhang X W,Kong L W,Li J J.Influence of dry and wet seasons on disintegration characteristics of basalt residual soil from the Leizhou Peninsula,China.Q J Eng Geol Hydrogeology,2018,51:450-460
3张先伟,李仁耿,郑永民,等.顺德强风化岩层预应力管桩桩端土软化的现场试验研究.中国科学:技术科学,2016,46:975-986
4 Ren D J,Shen S L,Cheng W C,et al.Geological formation and geo-hazards during subway construction in Guangzhou.Environ Earth Sci,2016,75:934
5吴帅峰,余永强,褚怀保,等.孤石爆破对土体扰动规律的试验研究.爆破,2015,32:12-16
6 An J,Tuan C Y,Cheeseman B A,et al.Simulation of soil behavior under blast loading.Int J GeoMech,2011,11:323-334
7 Wang Z,Lu Y.Numerical analysis on dynamic deformation mechanism of soils under blast loading.Soil Dyn Earthquake Eng,2003,23:705-714
8 Tong X,Tuan C Y.Viscoplastic cap model for soils under high strain rate loading.J Geotech Geoenviron Eng,2007,133:206-214
9 Henrych J.The Dynamics of Explosion and its Use.New York:Elsevier,1979
10 Gohl W B,Jeferies M G,Howie J A.Explosive compaction:Design,implementation and effectiveness.Géotechnique,2000,50:657-665
11王明洋,赵跃堂,钱七虎.饱和砂土动力特性及数值方法研究.岩土工程学报,2002,24:723-729
12 Omidvar M,Iskander M,Bless S.Stress-strain behavior of sand at high strain rates.Int J Impact Eng,2012,49:192-213
13林伟弟,李彰明,罗智斌.三轴冲击荷载作用下淤泥力学响应研究.岩土力学,2015,36:1966-1972
14聂庆科,李佩佩,王英辉,等.三轴冲击荷载作用下红黏土力学性状.岩石力学与工程学报,2009,28:1220-1225
15 Zhang X W,Kong L W,Yin S,et al.Engineering geology of basaltic residual soil in Leiqiong,southern China.EngGeol,2017,220:196-207
16 Ng C W W,Yung S Y.Determination of the anisotropic shear stiffness of an unsaturated decomposed soil.Géotechnique,2008,58:23-35
17 ASTM Standard D2487.Standard Practice for Classification of Soils for Engineering Purposes(Unified Soil Classification System).ASTMInternational,West Conshohocken,PA,2006
18 ASTM Standard D5311M-13.Standard Test Methods for Load Controlled Cyclic Triaxial Strength of Soil.ASTM International,West Conshohocken,PA,2013
19 Henkel D J,Gilbert G D.The effect measured of the rubber membrane on the triaxial compression strength of clay samples.Géotechnique,1952,3:20-29
20ХанукаевАН.矿岩爆破物理过程.刘殿中,译.北京:冶金工业出版社,1980
21 Suescun-Florez E,Omidvar M,Iskander M,et al.Review of high strain rate testing of granular soils.Geotech Test J,2015,38:20140267
22 Yang R,Chen J,Yang L,et al.An experimental study of high strain-rate properties of clay under high consolidation stress.Soil Dyn Earthquake Eng,2017,92:46-51
23 Mortezaie A R,Vucetic M.Effect of frequency and vertical stress on cyclic degradation and pore water pressure in clay in the NGI simple shear device.J Geotech Geoenviron Eng,2013,139:1727-1737
24 Felice C W.The response of soils to impulse loads using the split-hopkinson pressure bar technique.Dissertation for the Doctoral Degree.University of Utah,1985
25 Kumar R,Choudhury D,Bhargava K.Prediction of blast-induced vibration parameters for soil sites.Int J Geomech,2013,14:04014007
26 TM 5-855-1.Fundamentals of Protective Design for Conventional Weapons.Department of the Army,Washington,DC,USA,1986
27 Leong E C,Anand S,Cheong H K,et al.Re-examination of peak stress and scaled distance due to ground shock.Int J Impact Eng,2007,34:1487-1499
28 Kong W K.Blasting assessment of slopes and risks planning.AUST J Civil Eng,2012,10:177-192
29 Yoshimi Y,Oh-oka H.Influence of degree of shear stress reversal on the liquefaction potential of saturated sand.SOILS Found,1975,15:27-40
30张建民,王稳祥.振动频率对饱和砂土动力特性的影响.岩土工程学报,1990,12:89-97
31 Matsui T,Ito T,Ohara H.Cyclic stress-strain history and shear characteristics of clay.J Geotech Eng,1980,106:1101-1120
32 Yasuhara K,Yamanouchi T,Hirao K.Cyclic strength and deformation of normally consolidated clay.SOILS Found,1982,22:77-91
33张茹,涂扬举,费文平,等.振动频率对饱和黏性土动力特性的影响.岩土力学,2006,27:699-704
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