Experimental modeling of segmental shallow tunnels in alluvial affected by normal faults

Kiani, Majid; Akhlaghi, Tohid; Ghalandarzadeh, Abbas

doi:10.1016/j.tust.2015.10.005

Cited by 139 publications

(38 citation statements)

References 24 publications

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“…e seismic performance of tunnel mainly depends on the geological conditions to a certain extent; the portal section and fault dislocation zone of tunnel are generally the most severely sections of seismic damage. Many scholars have conducted research on antiseismic mechanism, measures, and antiseismic fortification length of tunnel by using methods of seismic damage investigation, theoretical analysis, numerical calculation, and model test for severe seismic damage sections mentioned above, and a large number of relevant research results have been achieved [1][2][3][4][5][6]. However, the survey of seismic damage after Wenchuan earthquake in China showed that the seismic damage of tunnel also mainly occurred in geological section at interface of soft and hard rock, and the tunnel linings were peeled, cracked, staggered, and collapsed in different degrees, such as the Baiyunding Tunnel from the G213 highway of Yingxiu to Dujiangyan in Sichuan Province and Longxi Tunnel on the Yingdu expressway.…”

Section: Introductionmentioning

confidence: 99%

“…However, the survey of seismic damage after Wenchuan earthquake in China showed that the seismic damage of tunnel also mainly occurred in geological section at interface of soft and hard rock, and the tunnel linings were peeled, cracked, staggered, and collapsed in different degrees, such as the Baiyunding Tunnel from the G213 highway of Yingxiu to Dujiangyan in Sichuan Province and Longxi Tunnel on the Yingdu expressway. e tunnel linings of interface section between soft and hard rock on these two lines showed circumferential cracks with 1 cm∼3 cm widths after earthquake [2,[7][8][9][10][11][12][13][14][15].…”

Section: Introductionmentioning

confidence: 99%

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Experimental Study on Characteristics of Seismic Damage and Damping Technology of Absorbing Joint of Tunnel Crossing Interface of Soft and Hard Rock

Wang

Yuan²,

Cui

et al. 2020

Shock and Vibration

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It has generally been believed that the serious seismic damage of tunnel mainly occurred in portal section and fault dislocation zone. However, the survey of seismic damage showed that the seismic damage of tunnel also mainly occurred in geological section at interface of soft and hard rock. Currently, merely scholars have made some research studies on characteristics of seismic damage and damping technology of tunnel crossing the vertical interface between soft and hard rock in high intensity area, and the mechanism of seismic damage has not been clearly revealed. Therefore, based on the Urumqi Metro Tunnel project in China, a three-dimensional six-degree-of-freedom shaking table model test was carried out. Through comparative analysis of peak ground acceleration (PGA), displacement difference at the interface between soft and hard rock, and structural safety factor under 5 kinds of conditions, the seismic damage characteristics of tunnel crossing interface of soft and hard rock were revealed, and a new damping technology of absorbing joint was proposed. The following findings can be drawn. (1) The seismic damage of tunnel is mainly affected by stratum inertial force under the homogeneous stratum of soft rock. The seismic damage of tunnel is mainly caused by the forced displacement (the displacement difference between the two sides of interface of soft and hard rock), followed by stratum inertial force under the geological condition of interface between soft and hard rock. (2) The conventional type of absorbing joint (only the second lining is set with absorbing joint) is used in tunnel lining structure, and the damping ratios of principal tensile stress, bending moment, and axial force of lining are above 47.5%, 40.7%, and 72.7%, respectively. Compared with conventional type of absorbing joint, the damping effect of new type of absorbing joint (staggered absorbing joints of primary support and secondary lining) is 19.9% higher than that of conventional type. (3) The new type of absorbing joint is recommended for tunnel crossing interface section of soft and hard rock. The specific implementation suggestions are as follows: the setting interval of second lining absorbing joint is the same as the length of lining formwork trolley, and the interval of primary support absorbing joint can be set according to excavation footage length. The filling materials in second lining absorbing joint can be shared with the rubber waterstop set in construction joint, and the primary support absorbing joint can be realized by injecting mixtures of rubber particles and shotcrete.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Experimental Study on Characteristics of Seismic Damage and Damping Technology of Absorbing Joint of Tunnel Crossing Interface of Soft and Hard Rock

Wang

Yuan²,

Cui

et al. 2020

Shock and Vibration

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“…erefore, it is necessary to systematically study the antibreaking technology of the stick-slip fault tunnels in order to improve the structural safety and stability. e shearing force and displacement caused by the fault stick-slip dislocation are the main reasons for structural damage of tunnels [7,8]. e antibreaking measures (such as structural strengthening or surrounding rock strengthening) can effectively resist many adverse influences induced by the stick-slip fault.…”

Section: Introductionmentioning

confidence: 99%

Model Tests on the Antibreaking Countermeasures for Tunnel Lining Across Stick‐Slip Faults

Cui

Wang

et al. 2020

Advances in Materials Science and Engineering

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In order to improve the structural safety and stability of the tunnels crossing stick-slip fault, an indoor model test on the effect of tunnel antibreaking measures under the influence of fault stick-slip movements was conducted. Using contact pressure, longitudinal strain, and safety factor, the antibreaking effect of tunnels was compared and analyzed under 5 kinds of operating conditions, mainly including no measures, structural strengthening, structural strengthening and reducing dislocation layer, structural strengthening and reducing dislocation joint, structural strengthening and reducing dislocation layer, and reducing dislocation joint. The results showed that the longitudinal strain and contact pressure of the tunnel changed markedly (from severe change to more uniform change) when the reducing dislocation measures were adopted in the test, reducing dislocation layer/joint or reducing dislocation layer and reducing dislocation joint. The effect of reducing the fault stick-slip dislocation on the tunnel structure is very limited by only taking structure strengthening measures. The effect of reducing the fault stick-slip dislocation on the tunnel structure is obvious by using the reducing dislocation method, and the minimum safety factor is increased by more than 8 times. The effect of resisting and reducing the fault stick-slip dislocation on the tunnel structure is remarkable by adopting the measures of the structural strengthening and reducing dislocation layer and reducing dislocation joint, and the minimum safety factor is increased by more than 25.45 times. The results can provide reference for the design of antibreaking for the stick-slip fault tunnel in high earthquake intensity and dangerous mountainous areas.

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“…Li et al [10] conducted a 3D physical model test to clarify the effect of the dipping formation and bidirectional excavation on the tunnel deformation: crown settlement, floor heave, and radial displacement of the equivalent sections in the physical model were investigated. Kiani et al [11] carried out a series of centrifuge model tests on segmental tunnels subjected to normal faulting and the physical modelling of a normal fault, a segmental tunnel in a centrifuge, and the results of nine centrifuge tests were described. Li et al [12] performed a large-scale geomechanical model test based on Zhaolou coal mine in China.…”

Section: Introductionmentioning

confidence: 99%

Instability Process of Crack Propagation and Tunnel Failure Affected by Cross‐Sectional Geometry of an Underground Tunnel

Hao

Shao-hua

Jin

et al. 2019

Advances in Civil Engineering

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The process of crack propagation and tunnel failure is affected by the cross-sectional geometry of an underground tunnel. In order to quantify the effect of section shape on the process of crack propagation in deep tunnels under high ground stress conditions, a total of four physical models with two cross-sectional shapes and twelve stress levels were designed and several large-scale physical model tests were conducted. The results indicated that, when the vertical stress is 4.94 MPa, the length and depth of the cracks generated in the rock surrounding the horseshoe tunnel are about eight times that around a circular tunnel. The position where the circumferential displacement of the horseshoe tunnel begins to be stable is about two, to two and a half, times that around a circular tunnel. After the deep chamber was excavated, continuous spalling was found to occur at the foot of the horseshoe tunnel and microcracks in the surrounding rock were initially generated from the foot of the side wall and then developed upwards to form a conjugate sliding shape to the foot of the arch roof, where the cracks finally coalesced. Discontinuous spalling occurred at the midheight of the side wall of the circular tunnel after excavation, and microcracks in the surrounding rock were initially generated from the midheight of the side wall and then extended concentrically to greater depth in the rock mass surrounding the tunnel. Tensile failure mainly occurred on the surface of the side wall: shear failure mainly appeared in the surrounding rock.

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Experimental modeling of segmental shallow tunnels in alluvial affected by normal faults

Cited by 139 publications

References 24 publications

Experimental Study on Characteristics of Seismic Damage and Damping Technology of Absorbing Joint of Tunnel Crossing Interface of Soft and Hard Rock

Experimental Study on Characteristics of Seismic Damage and Damping Technology of Absorbing Joint of Tunnel Crossing Interface of Soft and Hard Rock

Model Tests on the Antibreaking Countermeasures for Tunnel Lining Across Stick‐Slip Faults

Instability Process of Crack Propagation and Tunnel Failure Affected by Cross‐Sectional Geometry of an Underground Tunnel

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