中国地震
中國地震
중국지진
EARTHQUAKE RESEARCH IN CHINA
2009年
3期
265-273
,共9页
关键词:地震不稳定性%断层破裂%Weibull分布%断层本构关系%平衡路径曲线%应力突跳
關鍵詞:地震不穩定性%斷層破裂%Weibull分佈%斷層本構關繫%平衡路徑麯線%應力突跳
관건사:지진불은정성%단층파렬%Weibull분포%단층본구관계%평형로경곡선%응력돌도
Earthquake instability%Fault rupture%Weibull distribution%Fault constitutive relation%Equilibrium path curve%Stress jump
基于断层面强度的非均匀性,将断层面的宏观破裂过程看作是断面局部微元的破裂累积过程,假设断层局部微元强度遵循Weibull概率分布,从统计力学角度推导出了宏观的断层载荷.变形的全过程本构关系.采用一维地震力学模型,以远场位移a为控制变量,用稳定性理论研究了地震不稳定性问题.研究表明,系统刚度比(围岩刚度与断层刚度之比)β是影响地震发生的重要参数,只有当β<1时才会出现地震失稳,且应力突跳发生在平衡路径曲线的位移转向点,并给出了地震过程的3个重要参数(地震后断层半错距、地震应力降和释放的弹性能)的表达式.当β≥1时,不会发生地震,仅是缓慢的断层滑动,属于无震滑动.
基于斷層麵彊度的非均勻性,將斷層麵的宏觀破裂過程看作是斷麵跼部微元的破裂纍積過程,假設斷層跼部微元彊度遵循Weibull概率分佈,從統計力學角度推導齣瞭宏觀的斷層載荷.變形的全過程本構關繫.採用一維地震力學模型,以遠場位移a為控製變量,用穩定性理論研究瞭地震不穩定性問題.研究錶明,繫統剛度比(圍巖剛度與斷層剛度之比)β是影響地震髮生的重要參數,隻有噹β<1時纔會齣現地震失穩,且應力突跳髮生在平衡路徑麯線的位移轉嚮點,併給齣瞭地震過程的3箇重要參數(地震後斷層半錯距、地震應力降和釋放的彈性能)的錶達式.噹β≥1時,不會髮生地震,僅是緩慢的斷層滑動,屬于無震滑動.
기우단층면강도적비균균성,장단층면적굉관파렬과정간작시단면국부미원적파렬루적과정,가설단층국부미원강도준순Weibull개솔분포,종통계역학각도추도출료굉관적단층재하.변형적전과정본구관계.채용일유지진역학모형,이원장위이a위공제변량,용은정성이론연구료지진불은정성문제.연구표명,계통강도비(위암강도여단층강도지비)β시영향지진발생적중요삼수,지유당β<1시재회출현지진실은,차응력돌도발생재평형로경곡선적위이전향점,병급출료지진과정적3개중요삼수(지진후단층반착거、지진응력강화석방적탄성능)적표체식.당β≥1시,불회발생지진,부시완만적단층활동,속우무진활동.
In terms of the heterogeneity of fault plane strength, the macro rupture process of fault plane can be treated as the rupture accumulation process of local micro elements in fault surface. Assuming the strength of fault local micro elements follows Weibull probability distribution, the macro fault constitutive relation of load-deformation complete process can be derived from statistical mechanics viewpoint. Applying one dimension earthquake mechanics model and using far filed displacement a as control variables, the problem of earthquake instability is investigated by employing stability theory in this paper. The results show that system stiffness ratio (stiffness ratio of fault to surrounding rock)β is the important parameter to affect earthquake occurrence. The earthquake instability occurs only when β <1, and the stress jump appears at the displacement turning point of equilibrium path curve. The expression of three important parameters for earthquake (fault half-dislocation after earthquake, earthquake stress drop and elastic energy release) are also given. When β≥1, earthquake does not occur and fault only slips slowly without an earthquake.