House / soil movement

Here are the resources worth reading on the topic:

• Maintenance of Existing Foundations on Expansive Clay Soils (B-5002)
• Living With Expansive Soils
• MAINTENANCE OF SLAB-ON-GRADE FOUNDATIONS BUILT ON EXPANSIVE CLAY BASED SOILS
• Information on Soils and Foundations
• FOUNDATIONS IN EXPANSIVE SOILS (TM5-818-7)
• MINIMIZATION OF FOUNDATION MOVEMENT
• Expansive Soil
• Mr. Foundation
  

(mostly found through this search on google).

Most recommendations seem to center on around:

• Sloping soil away from foundation
  
• Watering regularly to prevent huge cracks from appearing (which allows for non-standard water flow)
  
• Monitor soil moisture (possibly with instruments at multiple locations around foundation?) - aka "soil resistivity" OR "soil moisture measurement"
  
• Consider setting up barriers to roots and/or water movement
• And of course, gutters