地裂缝及其灾害研究的新进展

已查明我国 2 6个省市出现具一定规模的地裂缝 1 0 0 3处 ,60 0 0多条。其中 80 %是构造地裂缝 ,它们是地壳浅表层破裂。区域地裂缝与强震区分布一致 ,活跃期也相吻合 ,它们是同一构造应力场作用的不同构造现象 ,区域地裂缝释放地壳应变能远超过同期强震能量释放的总和。作为动力源的地裂缝活动使同期地质体发生位移产生形变场和应力场 ,并通过地基使建筑物结构等失稳失效破坏成灾 ,估算全国地裂缝造成的损失为 91 .2亿元 ,其中华北区损失占 70 %。地裂缝已构成一个新的独立的灾种。

PROGRESS IN GROUND FISSURES AND ITS HAZARD RESEARCH

It generally discusses the main progress in ground fissures studyingin in our country's.Investigation showes that:there are 1 003 places (more than 6 000 strips) where ground fissures are on a certain extent scale and knockout in 26 provinces and cities in China.Among which tectonic ground fissures occupies about 80%.The ground fissures of wriggle fault occupies 15%～20.8% and that of territorial slight cracking occupies 79.2%～85% among tectonic ground fissures.Tectonic ground fissures are territorial superficial crack of lithosphere.They are domino effect of wriggle crack in rock and soil.　　According to the pattern of distribution,the degree of development,the type of cause of formation and tectonic background,it can be marked off four distributed regions of ground fissures such as the NANHUA,the big North of China,the Northeast and the West.In every place the degree of development of ground fissures is corresponding to the degree of lithosphere motion at the location.In the big North of China,the earth is basically steady once,and the length of the ground fissures with earthquake and without earthquake separately add up to 321 km and 497 km.In the West,the lithosphere is relatively unsteady,and that separately add up to 2 696 km and 2.5 km.In the Nanhua and the Northeast,lithosphere is relatively steady,and the non-seismic ground fissures develop.　　It can be found by historical data and apparatus that the motion of ground fissure may be divided into three active cycles by different scalar,such as 312 years on average and about 20 years of open-close periods and 4～5 years of impulsive periods in almost 700 years cycle.It often irregularly makes jumpiness,attenuation,silence and counter motion between the impulsive periods.　　The space location of ground fissures is identical with that of earthquakes in China,and both active cycles are also corresponding.They are tectonic phenomena in the same tectonic stress field.Ground fissures are representation of fast-sliding fault.Strong shock in the North part alternately appears with active climax of ground fissures.Either the north shocks and the south breaks or the south shocks and the north breaks.It indicates that lithosphere alternately released energy.Studying made know that the large energy released by lithosphere stain in large scale in north of China is far overrunning the summation of energy released by periodically strong shock.　　The inside stress engendered by motion of lithosphere drives fault and opens creak.Non-tectonic effectiveness is also one of forces that drive present ground fissures.The majority of territorial ground fissures is formed by tectonic effect.Lurking tectonic ground fissures appearing on the surface become tectonic ground fissures by the lure of non-tectonic factors,for example precipitation,irrigation or pumping the ground water.They remain not only the original crack form,but also the later crack form that formed by non-tectonic factors.　　The activity of ground fissures as original force displaces the geology object around it,engenders distortion field and stress field,induces structure's overbalance or invalidation.For example,civil construction destroying,ditch and dam break,lathe misplace,destroying the lifeline engineering,reduce the use-value of both side fields around metamorphose.According to up-to-date estimation the loss is up to 9.12 billion yuan by ground fissures in the whole country,70% of which is in the north of China,and the loss ground fissures in the four cities of Xi'an,Datong,Handan,Lingfen four cities occupies 29%.So ground fissures already become a new independent hazard.The process of its forming includes behavior,phenomena,and disaster.The behavior includes lithosphere motion and over-pumping the ground water.The phenomena include appearance of the ground fissure.Disaster is the breakage of field and construction.The corresponding measures are controlling its behavior,steadying its phenomena,protect against its disaster.　　Integrate the system of upper discovering as a new theory,and establish a new subject -that is the Hazard of Ground Fissures.