The bending mechanism of Anping ground fissure in the Hebei Plain, North China

Abstract

The Anping fissure is one typical and particular ground fissure in the North China Plain. This study was carried out in Anping area with geological means, such as surveying, mapping, trenching and drilling. The geological structure and disasters were analyzed by both qualitative and quantitative methods. The main conclusions are as follows: (1) Anping ground fissure is the local manifestation of regional tectonic stress field and is basically folding directional, hidden and intermittent. (2) Under the control of Shen-rao fault, Anping ground fissure was exposed and expanded by water-related human activities, and then was cracked by small-and medium-sized earthquakes. (3) The forming process followed the bending-cracking rules. The uplifting force from deep in the earth bent the entire overlying strata. The tangential stress below the ground surface counterbalanced the horizontal stress of soils, even breaking through their tensile strength and inducing cracks. The fissure was periodic and wavery, because the cracking force was proportional to the uplifting force but inversely proportional to the stratigraphic depth.

Shaking table tests of RC frame structure across the earth fissure under earthquake

“…In the literature, many studies have been carried out on earth fissures, most have focused on basic characteristic, formation mechanism, and spatial distribution. [15][16][17][18][19][20][21][22] Wang et al [15] provided detailed study on earth fissures distribution in Xi'an and proposed the corresponding measures to prevent damage resulting from the earth fissure. Mohseni et al [22] examined variations in the spatial patterns of soil-vegetation properties in the vicinity of subsidence-related earth fissures caused by groundwater overpumping over an arid ecotone situated in northeastern Iran.…”

Experimental study on Su-Xi-Chang earth fissures induced by repeated groundwater pumping and impounding

“…There are more than 3000 earth fissures distributed in over 700 places in the north China plain. Among them, 78% are non-structural (Xu et al 2015). Researches have shown that both internal and external dynamic geological processes and human engineering activities play crucial roles in their formation and evolution.…”

“…In fact, the impacts of groundwater activities on the strata have been observed in both horizontal and vertical directions. Even large block bendings have been found (Sheng et al 2003;Budhu 2008;Xu et al 2015). Some researchers believe that specific soil masses are characteristics of collapsibility and structural discontinuity.…”

Short syntheses of the tricyclic indole alkaloids cimitrypazepine and fargesine

“…Formation of the azepine ring via the carbon-nitrogen bond b is the most commonly used approach in total synthesis 6,7 although, the formation of carbon-nitrogen bond c 8 and carbon-carbon bonds a 5,9 and d 10 have been employed ( Figure 2). The assembly of both the pyrrole and azepine rings onto a functionalized benzene ring is more unusual but sequential f-e-b, 11 b then f, 12 and e then f 13 The tricyclic N-oxide alkaloid fargesine was isolated from the roots and stems of Evodia fargesii in 2006 4 and a total synthesis was reported by Jia et al 13 The fruits of the plant have been used in Chinese folk medicine as an analgesic and cough suppressant. The closely related non-oxidized alkaloid named cimitryptazepine was later identified in Black cohosh (Cimicifuga racemosa), a flowering plant native to eastern North America.…”