average traffic and tch blocking

It may lead to many correlations. An advantage if you specify your question. Perhap start from you problem or consideration to know the context.
If you talk about a dimensioning on air-IF of GSM, normally you need average traffic of busyhour derived from some of days. Hence you can estimate required number of trunk (TCH) to maintain TCH blocking rate value.
Basically, those things have relation but not close:
The higher average of traffic carried may lead to higher TCH blocking rate, but not always.
The higher TCH blocking rate of wholeday or even particular hour observation, not always mean the higher trafic volume being carried by radio resources. However, regardless of hardware problem (TRX or TCH unavailable), higher TCH blocking rate on particular busyhour mostly carried traffic so that the traffic utilization getting higher (doesn’t mean higher the traffic volume). Traffic utilization = traffic carried BH / traffic offer.
So what the heck is your question is?