An Analysis of NGI Simple Shear Apparatus for Cyclic Soil Testing

Shen, C-K; Sadigh, K.; Herrmann, Leonard R.

doi:10.1520/stp35675s

Cited by 30 publications

(11 citation statements)

References 6 publications

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“…A soil specimen is confined inside a flexible boundary to reduce the boundary effects. In addition, selecting a low height-to-diamater ratio will improve the uniformity of shear strain distribution along the specimen (Shen et al 1978). Over the last century, several versions of this machine have been built and tested while they differed in loading mechanism, specimen confinement method, instrumentation, and specimen sizes (Kjellman 1951;Budhu 1984;Airey and Wood 1987).…”

Section: Cyclic Direct Simple Shear Apparatusmentioning

confidence: 99%

Cyclic Direct Simple Shear Test to Measure Strain-Dependent Dynamic Properties of Unsaturated Sand

Ghayoomi

2017

Geotech. Test. J.

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The dynamic properties of a clean sand under different degrees of saturation were investigated using a modified custom built Direct Simple Shear (DSS) apparatus at the University of New Hampshire. The specific characteristics of the DSS were presented, and the testing procedures were discussed. The device used the axis translation and tensiometric techniques to control the matric suction in the soil specimen. The investigation on F75 Ottawa Sand showed a decrease in shear modulus and an increase in damping by increasing the shear strain over the tested range of strains for various degrees of saturation: dry, saturated, and partially saturated. The modulus reduction in the applied range of medium shear strains regardless of the degree of saturation demonstrated the capability of the DSS in consistently capturing the changes of dynamic properties. Experimental results indicated that the matric suction can have a substantial effect on the stiffness of the soil. However, the extent of this effect may depend on the induced strain level of the effective stress in unsaturated soil. In addition, partially saturated specimens resulted in lower dynamic compression.

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Section: Cyclic Direct Simple Shear Apparatusmentioning

confidence: 99%

Cyclic Direct Simple Shear Test to Measure Strain-Dependent Dynamic Properties of Unsaturated Sand

Ghayoomi

2017

Geotech. Test. J.

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“…The introduction of servo controlled cyclic loading, cell pressure, and bidirectional shear loading made the direct simple shear apparatus ever more popular in modeling liquefaction behaviors [13][14][15][16][17][18]. Although nonuniform stress distributions were existed within the simple shear specimen, the significance of the simple shear apparatus in geotechnical engineering was convinced by the previous researchers [13,[19][20][21][22][23][24][25]. In this research, the wires of the NGI simple shear device were replaced by cell pressure and the circumferential deformation was monitored by a circumferential deformation device; thus a clear and complete stress-strain boundary had been defined.…”

Section: Introductionmentioning

confidence: 99%

Radial Strain Behaviors and Stress State Interpretation of Soil Under Direct Simple Shear

Kang

Cheng

2015

Journal of Testing and Evaluation

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Radial strain behaviors and stress state interpretation methods of silica sand consolidated at different K 0 values under modified direct simple shear were investigated in this research. Consolidated drained triaxial compression test, direct shear box test, and wire reinforced direct simple shear tests were conducted and the test results were compared and linked with the modified direct simple shear tests. Based on the observed testing data, simple shear specimens with constant lateral stress exhibited relative small radial strain during shear, especially under small shear strains. After the peak shear resistance has mobilized, radial strain increased rigorously until the specimen failed. Confining pressure and K 0 values were found to have great deal of influence on the simple shear radial change. Two different methods were adopted to interpret the stress conditions within the simple shear specimen and the "pure shear" method was found more appropriate in interpreting the stress state in the modified direct simple shear test.

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“…The sample in this case represents a karstified rock mass. Comparison of the results of the numerical FEM model and the laboratory experiment in previous research (Shen et al 1978) shows that it is possible to minimize the influence of boundary conditions (elements) in the numerical model in such a way that the sample and membrane have similar elastic properties.…”

Section: Construction Pit Structural Elementsmentioning

confidence: 93%

Calibration of Rock Cutting Numerical Model based on Monitoring Data

Pavlić¹,

Bačić²,

Kovačević³

2019

JSM

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Prediction of the deformation increment and the final displacement of the rock cutting is a challenging task. Many ambiguities linked with unpredictable nature or rock mass make it difficult to apply the adequate contingency measures. Implementation of common approach, which includes modelling of discontinuity effects with estimated reduction of rock mass strength and modulus of elasticity, usually does not yield satisfactory results. Therefore, a calibration of FEM based numerical model was made by conducting parametric analysis which feeds upon data obtained from extensive on-site monitoring system. A step forward was made in description of numerical parameters of karst discontinuities through consideration of monitoring results, as well as excavation procedures, position, inclination and length of discontinuities and PDC (project design change). ABSTRAKRamalan kenaikan canggaan dan sesaran akhir pemotongan batu adalah satu tugas yang mencabar. Banyak kesamaran yang dikaitkan dengan sifat yang tidak dapat diramalkan atau jisim batu menyukarkan untuk menggunakan langkah kontingensi yang mencukupi. Pelaksanaan pendekatan biasa yang merangkumi pemodelan kesan ketakselanjaran dengan anggaran pengurangan kekuatan jisim batu dan modulus keanjalan, kebiasaannya tidak memberikan keputusan yang memuaskan. Oleh itu, penentukuran model berangka FEM dibuat dengan menjalankan analisis parametrik yang menggunakan data yang diperoleh daripada sistem pemantauan ekstensif di tapak. Satu penambahbaikan telah dibuat dalam penerangan parameter berangka ketakselanjaran karst dengan mempertimbangkan keputusan pemantauan serta prosedur pengorekan, kedudukan, kecenderungan dan panjang ketakselanjaran dan PDC (perubahan reka bentuk projek). Kata kunci: Jisim batu; kaedah pemerapan; karst; ketakselanjaran; pemodelan berangka Vedran Pavlic Hidroinzenjering d.o.o. Okucanska 30, 10 000 Zagreb Croatia

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An Analysis of NGI Simple Shear Apparatus for Cyclic Soil Testing

Cited by 30 publications

References 6 publications

Cyclic Direct Simple Shear Test to Measure Strain-Dependent Dynamic Properties of Unsaturated Sand

Cyclic Direct Simple Shear Test to Measure Strain-Dependent Dynamic Properties of Unsaturated Sand

Radial Strain Behaviors and Stress State Interpretation of Soil Under Direct Simple Shear

Calibration of Rock Cutting Numerical Model based on Monitoring Data

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