Deformation Measurement
1. Concept
Measures the deformation of building and its foundation’ with time, causes by the building load and external force. 
With the continuous development of urban planning and construction, many buildings, such as hydraulic structures, industrial and transportation buildings, tall buildings and underground resources are established throughout the country. Following this trend, a number of precision machinery, railway, scientific test equipment and facilities are installed. Due to various factors, buildings and its facilitated equipments in these projects will be distorted during using. This deformation within certain limits is a normal phenomenon, but if it exceeds prescribed limits, it will affect the normal use of the building and even threaten the safety of the buildings. Therefore, during the course of construction and using, they must be monitored, which is, deformation monitoring. 

Monitoring Station in front of dam of power plant

Monitoring Station after the dam of power plant

2. Reasons of Engender Deformation 
Many reasons can cause deformation, the two main reasons are
(1) Natural conditions and its change, which is caused by engineering geology, hydrogeology, soil physical properties and atmospheric factors. For example, the different geological conditions will cause the building uneven settlement, and make it to tilt or crack. 
(2) Building’s own reasons, which is its own load, structure, form and dynamic load (such as wind, vibration, etc.). 
In addition, the unreasonable factors in survey, design, construction and management will also lead to building deformation. 



3. The Task of Deformation Measurement 
Repeated observation on the set point (or certain part of building),in order to achieve the variation during each observation cycle. To measure the instantaneous deformation, we can use a variety of automatic recording instruments to measure the instantaneous position. 
Deformation measurement is divided into two types, vertical displacement based type and horizontal displacement based type. The former includes pit resilience measurement, foundation layer deposition measurement and settlement building measure, the latter includes tilt observation, displacement observation, crack deflection observation and observation. 
With the increase demand of building high-rise and the maintenance of ancient structures, deformation observations cause more and more attention, some people has already begun their study on the theory and methods of optimized deformation control network. Besides continuing to use some effective methods and the traditional observation instruments, some new instruments, such as round laser measuring instrument, automatic vertical instrument and electronic inclinometer will be gradually applied. This development must bring more automation to measuring process. Observation data processing has widely applied methods of mathematical statistics to test point stability. The development from a single variable statistical analysis to the multivariate qualitative and quantitative statistical analysis provides more reliable guarantee to the safety of building. 

SOUTH has made outstanding contribution to this kind of project! 
First, we have introduced a series of structural observation products,
1, Total station automatic deformation monitoring system
Use Leica, Trimble and Sokkia robotic total station with our automatic deformation monitoring software to achieve three-dimensional structure of displacement and deformation automatic monitoring. Its advantage is stable and reliable, low measurement cost and multiple measuring points. 
System Features
(1) Data interface flexible, wired and wireless connection optional.
(2) System runs stable, software uses dynamic link library, which shortens the communication delay with total station, much better than general monitoring software. 
(3) Support connection with multiple brands of instruments, such as Leica, Trimble and Sokkia. Other software does not have this feature.
(4) Our software uses real-time differential analysis techniques to obtain good measurement results at the same time saving the step of taking temperature and air pressure. 
(5) The function modules can be customized according to users. Application objects include high-speed rail bridges, subway tunnels, high slope, dam, high building construction, all kinds of traffic tunnels, tailings, etc.. 

2. GPS monitoring system 

3. Tilt monitor - tilt sensors

4. Automatic leveling - static level 

5. Automatic inclinometer 
So far from 2009, we participated in a number of deformation measurement projects, including 
(1) Deformation influence of Pearl River channel riprap operation to Pearl River tunnel (date, Oct, 2009.), 
(2) Guangzhou Huangsha subway station deformation monitoring. (date, Sep, 2009)
(3) Foundation construction's deformation effect to subway tunnel. (date, Aug, 2009)