HUANG Lu-yuan, YANG Shu-xin, CUI Xiao-feng, et al. Analysis of characteristics of measured stress and stability of faults in North China[J]. 2013, 34(S1).
HUANG Lu-yuan, YANG Shu-xin, CUI Xiao-feng, et al. Analysis of characteristics of measured stress and stability of faults in North China[J]. 2013, 34(S1).DOI:
The hydraulic fracturing and stress relief measurement data of North China was collected mainly from “Fundamental database of crustal stress environment in continental China”. The entries of in situ stress data are 1 017. The characteristics of macroscopic stress field in North China and study regions are investigated. The results are as follows: (1) The maximum horizontal stress and minimum horizontal stress all increase linearly with depth. (2) The intermediate regression value of (at 2 000 m depth) is various in study regions; and the basic characteristic of magnitude is high in east and weak in west. (3) The range of the lateral pressure coefficient Kav=225/D+0.61 with depth is: 15/D+0.42≤Kav≤1 030/D+0.76. The distribution of Kav is scattered in superficial crust
becomes more concentrated in the deeper crust and trends to 0.61. At a critical depth of 577 m Kav equals to 1 which indicates the transition from horizontal to vertical stress domination. (4) The predominant directions of are nearly E-W
NEE-SWW and NE-SW in east regions of North China. The directions of in study regions in and around Ordos block are mainly NE-SW and NEE-SWW. In study regions of North China Plain
the directions are dominantly shown as NE-SW; and NNW-SSE
and some directions are NW-SE. Fault stability in North China are investigated: The stress difference at depths bellow 500 m has not reached the critical value of fault activity; and stress difference at depth above 500 m has reached or exceeded the sliding friction threshold of the strike-slip fault.