对汶川地震断层带进行了跨断层的渗透率测量.结果显示汶川地震断层由低渗的核部(2.4×10-19～3.8×10-16m2)、高渗的破碎带(3.7×10-16～3.0×10-15m2)以及含裂隙原岩(6.0×10-18～4.3×10-13 m2)组成(有效压力40 MPa),其中新鲜断层泥具有最低的渗透率.断层泥和两侧原岩由于渗透率低,阻碍流体跨断层带流通,断层带内的流体活动局限在高渗的破碎带中,这一结果与断层岩显微结构和粒度分布特征能很好的吻合.对汶川地震同震热压作用发生的条件进行了探讨,结果显示,约2 km以下汶川地震主滑动带具有发生热压作用所要求的低渗透率特征.%Cross-fault permeability measurement was conducted on the Wenchuan earthquake fault. The results showed that this earthquake fault consists of fault core with low permeability (2. 4×10-18-- 3. 8×10-16 m2), highly permeable damaged zone (3. 7×10-16 - 3. 0×10-15 m2) and the fractured protolith (6.0×10-18 - 4. 3×l0-13m2) (40 Mpa effective pressure) , among which fresh gouges on the main slip surface are the most impermeable. Impeded by the impermeable protolith and fault gouge, cross-fault fluid flow was inhibited and fluid activity was confined within the damaged zone. This recognition is consistent with microstructure and grain size distribution of fault rocks. Condition of co-seismic thermal pressurization was calculated and the results showed that at depth greater than 2 km, the main slip zone of Wenchuan earthquake has the characteristics of low permeability for thermal pressurization to occur.
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