Study of the seismic performance of hybrid A-frame micropile/MSE (mechanically stabilized earth) wall

The Hybrid A-Frame Micropile/MSE （mechanically stabilized earth） Wall suitable for mountain roadways is put forward in this study： a pair of vertical and inclined micropiles goes through the backfill region of a highway MSE Wall from the road surface and are then anchored into the foundation. The pile cap and grade beam are placed on the pile tops, and then a road barrier is connected to the grade beam by connecting pieces. The MSE wall＇s global stability, local stability and impact resistance of the road barrier can be enhanced simultaneously by this design. In order to validate the serviceability of the hybrid A-frame micropile/MSE wall and the reliability of the numerical method, scale model tests and a corresponding numerical simulation were conducted. Then, the seismic performance of the MSE walls before and after reinforcement with micropiles was studied comparatively through numerical methods. The results indicate that the hybrid A-frame micropile/ MSE wall can effectively control earthquake-induced deformation, differential settlement at the road surface, bearing pressure on the bottom and acceleration by means of a rigid-soft combination of micropiles and MSE. The accumulated displacement under earthquakes with amplitude of 0.1-0.5 g is reduced by 36.3%-46.5%, and the acceleration amplification factor on the top of the wall is reduced by 13.4%, 15.7% and 19.3% based on 0.1, 0.3 and 0.5 g input earthquake loading, respectively, In addition, the earthquake-induced failure mode of the MSE wall in steep terrain is the sliding of the MSE region along the backslope, while the micropiles effectively control the sliding trend. The maximum earthquake-induced pile bending moment is in the interface between MSE and slope foundation, so it is necessary to strengthen the reinforcement of the pile body in the interface. Hence, it is proven that the hybrid A-frame micropile/MSE wall system has good seismic performance.

Behaviour of Batter Micropiles Subjected to Vertical and Lateral Loading Conditions

Micropiles are drilled and grouted piles having diameter between 100 to 250 mm. Due to its small diameter, it is suitable for low headroom and limited work area conditions. It can be installed without noise nuisance, without vibrations to surrounding soils and structures and without disruption to the production operations in industries which makes micropiles suitable for underpinning and seismic retrofitting of structures. It is necessary to therefore understand the behaviour of micropiles under different loading conditions. This work is on vertical and battered micropiles with different length/diameter ratio (L/D) subjected to vertical and lateral loading conditions. Batter angles had a significant influence on both the vertical and lateral load carrying capacity. The ultimate vertical load was found to increase upto a 30°batter. The ultimate lateral load was found to increase significantly with increasing L/D ratios upto an L/D ratio of 30 for vertical and 48 for battered piles, beyond which the increase was found to be not significant. In general, negative battered micropiles offered more lateral resistance than positive battered micropiles. The results of the study indicated that the ultimate load capacity and mode of failure of the micropiles are a function of the angle of batter, direction of batter and the L/D ratio for vertically and laterally loaded micropiles.

Mechanism of Ganlu Xiaodu MicroPill against COVID-19 based on network pharmacology and molecular docking method

Objective: To analyze the potential active components and molecular mechanism of Ganlu Xiaodu MicroPill in the treatment of COVID-19 by network pharmacology and molecular docking. Methods: the active chemical constituents and action targets of Ganlu Xiaodu MicroPill were searched by TCMSP and BATMAN-TCM platform, and the key targets were matched with the COVID-19 targets searched by CTD database. The core targets were selected and analyzed by GO and KEGG enrichment analysis by R software to predict the action mechanism of traditional Chinese medicine compound. The key component sets were docked with 3CLpro and ACE2. Results: 138 active components and 53 key targets were obtained. There are 1298 items in GO biological process, 59 items in cell composition, 62 items in molecular function, and 120 items enriched in KEGG pathway. Results: molecular docking showed that the affinity of 20 chemical components such as quercetin, luteolin and kaempferol with ACE2 and 3CLpro was higher than that of ribavirin and chloroquine. Conclusion: Ganlu Xiaodu MicroPill may regulate and interfere with SARS-CoV-2 infection through antivirus, inhibition of inflammatory factors and regulation of immunity, which fully reflects the therapeutic advantages of multi-components, multi-targets and multi-pathways of traditional Chinese medicine.