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Study on Configuration Method and Physical-mechanical Properties of Similar Materials for Visual Soft Soil Tunnel Model Test
(1. Guangzhou Metro Design & Research Institute Co., Ltd., Guangzhou 510010; 2. School of Civil Engineering, Southwest Jiaotong University, Chengdu 610031; 3. School of Civil Engineering, Chongqing University, Chongqing 400045; 4. School of Civil and Architectural Engineering, Hainan University, Haikou 570228)
Abstract Visual model tests are an effective means to clarify the triggering mechanisms of chain accidents induced by soft soil tunnel excavation, and reasonably proportioned similar materials are key to ensuring the reliability of model tests. Transparent similar materials of soft soil were configured using n-dodecane, 15# white oil, fused silica sand, and nano-scale white carbon black. Through density and oil content tests, standard consolidation tests, and consolidated quick shear tests, the mechanical and deformation characteristics of the configured materials were analyzed.The results show that the density of similar materials ranges between 1.30 g/cm3 and 1.59 g/cm3, the oil content between 36.13% and 124.71%, the initial void ratio between 0.70 and 2.34, the compression coefficient between 0.09MPa-1 and 1.04 MPa-1 , the compression modulus between 0.96 MPa and 20.11 MPa, the cohesion between 2.3 kPa and 31 kPa, and the internal friction angle between 14.82° and 27.07°, being similar to natural soft soil. The e-p curves of the samples exhibit a clear "concave upward" shape, and the e-lgp curves show an approximately linear downward trend. The consolidation coefficients of samples for each mix group range between 7.87×10-4 cm2/s and 2.02×10-2 cm2/s, being consistent with the value ranges for natural soft soil. The normalized shear stress-shear displacement curves of the transparent soft soils are identical to those of natural soft soil, both showing the strain hardening characteristics.
Abstract：
Visual model tests are an effective means to clarify the triggering mechanisms of chain accidents induced by soft soil tunnel excavation, and reasonably proportioned similar materials are key to ensuring the reliability of model tests. Transparent similar materials of soft soil were configured using n-dodecane, 15# white oil, fused silica sand, and nano-scale white carbon black. Through density and oil content tests, standard consolidation tests, and consolidated quick shear tests, the mechanical and deformation characteristics of the configured materials were analyzed.The results show that the density of similar materials ranges between 1.30 g/cm3 and 1.59 g/cm3, the oil content between 36.13% and 124.71%, the initial void ratio between 0.70 and 2.34, the compression coefficient between 0.09MPa-1 and 1.04 MPa-1 , the compression modulus between 0.96 MPa and 20.11 MPa, the cohesion between 2.3 kPa and 31 kPa, and the internal friction angle between 14.82° and 27.07°, being similar to natural soft soil. The e-p curves of the samples exhibit a clear "concave upward" shape, and the e-lgp curves show an approximately linear downward trend. The consolidation coefficients of samples for each mix group range between 7.87×10-4 cm2/s and 2.02×10-2 cm2/s, being consistent with the value ranges for natural soft soil. The normalized shear stress-shear displacement curves of the transparent soft soils are identical to those of natural soft soil, both showing the strain hardening characteristics.
HE Shengya1 LI Liang1 LI Hengyi1 ZHANG Jianjing2 YE Liang1 WEN Haijia3 DUAN Huchen? XIE Peng?
.Study on Configuration Method and Physical-mechanical Properties of Similar Materials for Visual Soft Soil Tunnel Model Test[J] MODERN TUNNELLING TECHNOLOGY, 2024,V61(4): 202-209
2024, Vol. 61 