Stability analysis of statically indeterminate blocks in key block theory and application to rock slope in Jinping-I Hydropower Station

Sun, Guanhua; Zheng, Hong; Huang, Yaoying

doi:10.1016/j.enggeo.2014.09.012

Cited by 36 publications

(12 citation statements)

References 25 publications

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“…Block theory was early proposed by Dr Shi in the 1970s, later in 1985, professor Goodman and Dr Shi wrote their first book, which heralded the formal formation of the block theory . Since it was proposed, the block theory had rapidly developed in such areas as block identification, uncertainty analysis, and support design, and was also wildly used in many fields, including the slopes, tunnels, and dam foundations . The existing researches were mainly static analysis, and the earthquake action is reduced to a constant inertia force imposed on the rock block, which is called as the quasi‐static method .…”

Section: Introductionmentioning

confidence: 99%

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Seismic stability analysis of a rock block using the block theory and Newmark method

Sheng

Tang

et al. 2019

Num Anal Meth Geomechanics

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Summary Seismic stability analysis of a rock block is an important issue in the field of rock mechanics and rock engineering. To solve this problem, the block theory and the Newmark method are combined, and a general method for seismic response of a rock block is introduced. First, the formation method of a three‐dimensional rock block, which includes establishing a topological relationship among the block‐polygon face‐edge‐vertex and dividing a complex block into convex subblocks, is presented, and the simplex integration method is employed to calculate the volume of a rock block and the areas of the polygonal faces. Second, the assumptions and algorithms of the general method for seismic response of a rock block are detailed. The dynamic analysis is carried out in time step. In each time step, the key technologies including analysis of the seismic force and motion mode, trial of the incremental displacement, check for the block entrance, and update of the motion parameters are performed in order. Last, two verification examples and three application examples including a wedge, a rock block of slope, and a combined rock block are used to analyze the correctness and practicality of the general method. The results show that, for a given ground motion record, the Newmark program can effectively simulate the dynamic response process of the motion mode, velocity, and safety factor of the rock block, and the permanent displacement under the earthquake action is obtained, which provides a quantitative parameter to evaluate the dynamic stability of a rock block.

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Section: Introductionmentioning

confidence: 99%

“…12 Since it was proposed, the block theory had rapidly developed in such areas as block identification, uncertainty analysis, and support design, [13][14][15][16][17] and was also wildly used in many fields, including the slopes, tunnels, and dam foundations. [18][19][20][21][22][23][24] The existing researches were mainly static analysis, and the…”

mentioning

confidence: 99%

Seismic stability analysis of a rock block using the block theory and Newmark method

Sheng

Tang

et al. 2019

Num Anal Meth Geomechanics

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“…In practice, not only the failure mechanism but the secure method used in the unstable engineering work should be studied. Many publications have shown that the instability of rock engineering is often manifested in the form of the slip of the blocks formed by the intersection of joints [11][12][13][14][15]. The methods used to judge the block stability and determine the key blocks show that block stability is dominated by shear behavior of rock joints.…”

Section: Introductionmentioning

confidence: 99%

Dynamic Shear Strength of Rock Joints and Its Influence on Key Blocks

Wang

Xiu

2019

Geofluids

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Shear strength deterioration of rock joints and its induced instability of key blocks subjected to dynamic disturbance constitute the mechanism of many geological disasters such as rockburst, landslide, and rockfall. In this study, the influence of dynamic disturbance on rock joints was quantified in the form of stress, of which model was established by quasistatic method. The dynamic shear strength of rock joints was analyzed theoretically following the Coulomb-Navier criterion and further investigated experimentally by split Hopkinson pressure bar (SHPB) tests with impact velocities of 4.850 m/s, 8.722 m/s, 12.784 m/s, and 16.935 m/s. The effect of engineering disturbance on shear strength of rock joints was measured, and a degradation coefficient was used to describe it quantitatively. Considering the degradation of dynamic shear strength of rock joints and its influence on block stability, the method for determining key blocks under dynamic disturbance was given. Implementing this method into the program of Geotechnical Structure and Model Analysis-3D (GeoSMA-3D) developed by the authors’ team, the visualization of key blocks was achieved. From theoretical analysis and experimental investigation, it was figured out that the shear strength of rock joints is degraded under dynamic disturbance. The degradation of friction angle becomes more sensitive than that of cohesion. Additionally, numerical results show that the number of key blocks was increased with the increasing impact velocities.

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“…The engineering geological research of the left bank in the Jinping I Hydropower Station can be supplied by some relevant references [4~5]. The stability evolution due to excavation of the left bank rock slope of Jinping-I Hydropower Station is systematically studied with an improved block theory by Sun et al [6]. As we know, Sarma's method is very applicable to the analysis of rock slopes.…”

Section: Introductionmentioning

confidence: 99%

Stability Evolution of a Large Rock Block Revealed in the Excavation Process of the Left Slope of Jinping-I Hydropower Station Based on the Proposed Sarma's Method

Chen¹,

Sun²,

Zheng³

2015

Proceedings of the 2015 International Conference on Architectural, Civil and Hydraulics Engineering

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Abstract. There is a latent large block near the dam abutment of Jinping-I hydropower station, the stability of which is very important in the excavation process. As we know, Sarma's method is able to evaluate the stability of rock slopes with complex structural planes, because it takes into account the mobilization of internal strength of potential landslides. In the presence of multiple rock layers, however, no unified way is available to calculate the total strength on the slice interface, although in most cases the equivalent strength parameters are taken as the weighted averages of strength parameters of all layers. From the assumption that the normal pressure along the slice interface takes on a triangular distribution, we derive the equivalent strength parameters of the slice interface. Moreover, we discuss the influence of different selections of equivalent strength parameters of the slice interface on the factor of safety of a rock slope from a hydropower station in construction, with the conclusion that the difference might be appreciable. At last, based on the proposed procedure the stability evolution of the large rock block in excavation process is discussed. Its stability is increased before elevation 1840 m is reached because the upper portions of the blocks are removed, which help slide. After that, however, the stability is decreased gradually because the lower anti-sliding portions are removed little by little, which help stabilize the slip bodies. After the sliding body is wholly revealed, the factor of safety is 2.83, which is higher than that of sliding body corresponds to the dam crest and lower than that of the maximum in excavation process.

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Stability analysis of statically indeterminate blocks in key block theory and application to rock slope in Jinping-I Hydropower Station

Cited by 36 publications

References 25 publications

Seismic stability analysis of a rock block using the block theory and Newmark method

Seismic stability analysis of a rock block using the block theory and Newmark method

Dynamic Shear Strength of Rock Joints and Its Influence on Key Blocks

Stability Evolution of a Large Rock Block Revealed in the Excavation Process of the Left Slope of Jinping-I Hydropower Station Based on the Proposed Sarma's Method

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