You might find some hints in the German Journal of Human Resource Management 2016, Vol. 30(3-4) 225–245.

http://gjh.sagepub.com/content/current

You might benefit from considering issues from industrial anthropology and sociology that have been developed via fieldwork. The following article deals with silencing behaviors and a number of other social processes.

Bruce Fortado (1994). Informal Supervisory Social Control Strategies. Journal of Management Studies, 31(2), 251-274.

You might also find an article written by Bruce Fortado and Lawrence O'Brien (2008), Exploring Peer Discipline: A Financial Services Field Study, of interest. This paper is available on Researchgate.

The following article, which is available on Researchgate, certainly deals with a service situation, a cultural change and silencing behaviors, albeit, I am not sure this is what you had in mind.

Bruce Fortado and Paul Fadil (2014). The yin and yang of introducing a sales culture: The Amalgam Bank case.  Competitiveness Review, 24(5), 444-462.

Some people question whether one can effectively silence employees in an ongoing relationship, because they may find other informal means to express their interests and discontent.  One might call this "getting even" or "evening the score." These sorts of subjects are dealt with in the following article, which is also available on Researchgate:

Bruce Fortado (2001).  The Metamorphosis of Workplace Conflict. Human Relations, 54 (9), 1189-1221.

Good luck with your project, Bruce

 Dear Sascha, your advice is a guide for us. Thanks for your interest.

Hi,

Maybe this paper could help ?

Understanding individual responses to failure by the organisation to fulfill its obligations: examining the influence of psychological capital and psychological contract type

By: O'Donohue, Wayne; Martin, Angela; Torugsa, Nuttaneeya (Ann)

Human Resource Management Journal Volume: 25 Issue: 1 Pages: 131-147 Published: JAN 2015

 Abstract

This study advances both psychological contract (PC) and psychological capital (PsyCap) research by testing a novel theoretical model predicting likely worker response, as a joint function of an individual's level of PsyCap and PC type, to perceived failure by the organisation to meet its obligations to the worker-organisation relationship. With a large emergency services organisation using volunteer workers as the research context, the study presents the first empirical evidence from a sample of 592 volunteers that the integrated application of PC and PsyCap theory can contribute to a better understanding of individual responses to an organisation's failure to affirm ongoing support for the volunteer-organisation relationship.

Dear Bruce,

Actually the Yin and Yang theory directly related to our study topic. Because, employees' silence behaviours commonly stem from employers who are their opposite pole. As you say in your study, 'Every rise transforms into a fall. Within each victory, the seeds of the opposite's resurgence are planted (Fortado and Fadil, 2014)'.

Furthermore, peer discipline theory also related to empowerment practices and silence behaviours. Employees will be more likely to speak up their opinions when they believe that their position supported by other members of organization. So peer discipline may be beneficial for resolving silence spirals.

Thanks so much Professor. Your wisdom will contribute to us a lot.

Dear Avisheg,

In common with psychological capital (PsyCap), one of the sub-dimension of psychological empowerment (PE) is self-efficacy (believing in own ability to put in the necessary effort to succeed at challenging tasks, O'Donohue et al., 2015). So, the study you mentioned above is crucial for our research. 

Thanks for your attention and time.