超固结地层发生地面沉降需要一个大于超固结应力的起始附加应力来驱动。

For over-consolidated strata, land subsidence usually occurs under the critical condition that initial additional stress is larger than over-consolidation stress.

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钻进松软、非固结，通常是浅地层时，通过仅仅依靠液力冲击载荷去冲蚀破碎钻头下的岩石。

To drill soft, unconsolidated, usually shallow formations by eroding the "rock" below the bit by hydraulic impact loading alone.

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而在以粘土为主要胶结物的地层中，当开始产水后，水溶解地层中的胶结物，降低了地层固结强度。

In the stratum taking clay as main cement, water dissolves the cement in the stratum after beginning to produce water, and which reduced the consolidation intensity of stratum.

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