关于地基阻尼比测试分析方法的讨论和改进

Measuring and Analyzing Methods Improvement for Subsoil Damping Ratio

近年因编制国家液压振动台基础技术规范,由于地基阻尼比很重要,须对国内外某些主要测试和分析方法有所了解、研究,并作讨论和改进。本文介绍了切线法、点峰法、双峰法、多峰法、比拟法等方法的优缺点:点峰法可用线位移响应曲线相对宽度左半宽得出,阻尼比偏低,不宜用于需用阻尼控制共振的大型强振台基础设计;多峰法计算出的阻尼比值较大,可用于大型振动台基础的设计;对弹性半空间理论实用化的莱斯默比拟法,通过实测和论证,作了修正,用于新编规范,提高了我国长期以来使用的小阻尼比值。既能与国际接轨,又更为实用,且不失安全,经济效益显著。

The national technical code for hydraulic Vibrator foundation has been compiled in recent years. The subsoil damping ratio is very important, and needs to understand some main domestic and foreign measuring and analyzing methods, to make further discussion and improvement. The advantages and shortcomings of methods of tangent ,point-peak, two point-peak, multi-point-peak, and analog method are presented. The damping ratio of multi-peak method which may be derived by using the left width of linear displacement response curve is lower , and can not be applied to the design of large-sized strong vibrating foundation of which resonance shall be con- trolled, but damping ratio calculated by multi-peak method is larger and works well. Through measurement and verification, the practical Lsmers~ analog method of elastic semi-space theory is modified and applied to the new code, then the domestic damping ratio being lower for a long time will be raised. It is close to international lev- el, and will be more practical and safe,with notable economic benefit.