14. A method comprising: obtaining documents comprising unstructured text data from a service events database, the unstructured text data comprising unstructured service request summaries relating to respective service events; assigning each of the documents to one or more of a plurality of clusters based at least in part on one or more topics identified from the unstructured text data using at least one topic model; generating multiple distinct visualizations of a selected one of the clusters including at least: a bigram visualization of a plurality of term pairs from the selected cluster; and a summarization visualization of representative term sequences from the selected cluster; permitting user entry of a label for the selected cluster via a labeling interface; and updating the service events database to indicate a user-entered label for the selected cluster; wherein the obtaining, assigning, generating, permitting and updating are performed by a processing platform comprising one or more processing devices.
14. A method comprising: obtaining documents comprising unstructured text data from a service events database, the unstructured text data comprising unstructured service request summaries relating to respective service events; assigning each of the documents to one or more of a plurality of clusters based at least in part on one or more topics identified from the unstructured text data using at least one topic model; generating multiple distinct visualizations of a selected one of the clusters including at least: a bigram visualization of a plurality of term pairs from the selected cluster; and a summarization visualization of representative term sequences from the selected cluster; permitting user entry of a label for the selected cluster via a labeling interface; and updating the service events database to indicate a user-entered label for the selected cluster; wherein the obtaining, assigning, generating, permitting and updating are performed by a processing platform comprising one or more processing devices. 16. The method of claim 14 further comprising generating a contrastive topic visualization for multiple topics corresponding to multiple ones of the clusters.