Stress Monitoring for Anchor Rods System in Subway Tunnel Using FBG Technology

This paper presents a model test, used on the tunnels on Xi’an Metro Line 2, as the prototype for evaluating the reinforcing effect of the anchor rod in tunnel construction in loess areas. An independently designed fiber Bragg grating (FBG) sensor was used to monitor the seven strain conditions of the rock bolts during the construction. The result shows that the axial stress of the rock bolt changes after the excavation and increases steadily with the growing pressure in the wall rock. Results additionally show that the anchor rods at the tunnel vault are subjected to a compressive stress that remains relatively constant after the primary and the secondary lining, while those at the spandrel and the corner of the tunnel are subjected to increased tensile stress. This paper demonstrates the feasibility and the superiority of FBG technology for tunnel model tests

The eleven queens' Qos Ordos and the Imperial ancestral sacrifice under the Mongol-Yuan Dynasty

This paper collects the Chinese sources and depicts the Qoš Ordo as a form of Ordo under the Mongol-Yuan Dynasty, referring to the ordos administrated by the deceased emperors’ widowed queens. After the widows’ death, their ordos were inherited by other imperial female members. The institution of Qoš Ordo took its origin in Chinggis Qan’s Four Great Ordos; it experienced an evolution from the steppe to North China in the mid-13th century, probably under Qublai’s reign. By the end of the Yuan Dynasty during the mid-14th century, the Chinese sources attested to Eleven Queens’ Ordos. This paper argues that the Eleven should be identified with the eleven deceased Mongol emperors who were worshipped in imperial rituals, which indicates not only the Chinese influenced the Imperial Ancestral Temple (太庙), but also the Mongolian traditional sacrificial ritual (Mong. tüleši)

Changes of deep Pacific overturning circulation and carbonate chemistry during middle Miocene East Antarctic ice sheet expansion

East Antarctic ice sheet expansion (EAIE) at similar to 13.9 Ma in the middle Miocene represents a major climatic event during the long-term Cenozoic cooling, but ocean circulation and carbon cycle changes during this event remain unclear. Here, we present new fish teeth isotope (epsilon Nd) and benthic foraminiferal B/Ca records from the South China Sea (SCS), newly integrated meridional Pacific benthic foraminiferal delta O-18 and delta C-13 records and simulated results from a biogeochemical box model to explore the responses of deep Pacific Ocean circulation and carbon cycle across EAIE. The epsilon Nd and meridional benthic delta C-13 records reveal a more isolated Pacific Deep Water (PDW) and a sluggish Pacific meridional overturning circulation during the post-EAIE with respect to the pre-EAIE owing to weakened southern-sourced deep water formation. The deep-water [CO32-] and calcium carbonate mass accumulation rate in the SCS display markedly similar increases followed by recoveries to the pre-EAIE level during EAIE, which were probably caused by a shelf-basin shift of CaCO3 deposition and strengthened weathering due to a sea level fall within EAIE. The model results show that the similar to 1 parts per thousand positive delta C-13 excursion during EAIE could be attributed to increased weathering of high-delta C-13 shelf carbonates and a terrestrial carbon reservoir expansion. The drawdown of atmospheric CO2 over the middle Miocene were probably caused by combined effects of increased shelf carbonate weathering, expanded land biosphere carbon storage and a sluggish deep Pacific meridional overturning circulation. (C) 2017 Elsevier B.V. All rights reserved