Study On The Testing Apparatus And Method For Strain Modulus E_v2

Strain modulus Ev2 is an index which is used to estimate the construction quality ofroadbed and it can properly reflect the bearing capacity of the roadbed. Strain modulusEv2 testing method is the same with that in supervise and control testing of groundworkconstruction quality of railway, road, airfield, city traffic, dock and industry and civilconstruction. Strain modulus Ev2 test is from stress σ and center subside quantity s underthe loading plate. σ and s can be attained from testing which use round loading plate andload equipment to the first load and unload and then the second load to ground. Thevalue of strain modulus Ev is the slope of secant from 0.3 σ1max (the most stress of thefirst load) to 0.7σ1max of the stress-subside quantity curve. Ev1 is the strain modulus ofthe first loading test, and Ev2 is the strain modulus of the second loading. Several parameters commonly used to control the quality of roadbed are introducedin this paper. Now, modulus of roadbed reaction K30 is an index which is used to controlthe intensity and strain index of railway roadbed construction quality. K30 is the slope ofone line from origin to point which is corresponding to 1.25mm subside quantity of loadintensity-subside quantity (σ—s) curve when the first load testing is taking. Strainmodulus Ev2 test avoid the effect of plastic transfiguration of filling, and it can reflectbetter the real capability of roadbed earth than modulus of roadbed reaction K30. Now, strain modulus Ev2 has been used to control the special railway passengertraffic line roadbed load quality, but the testing apparatus and correlative technologicalstandard is still lacked in our country. It is one bran-new problem from basic regulate,apparatus, testing point to result computing for strain modulus Ev2 testing. So it isnecessary to study testing apparatus and method and correlative standard for strainmodulus Ev2 for satisfying the construction of the special railway passenger traffic line. Aim at this instance, testing apparatus has been developed which is fit for oursituation of our country, testing method and testing point has too been brought forward,data processing software has been exploited in this paper. These apparatus include finecontrollable loading system which can exactly gradually load and unload to bearingboard, subside testing apparatus that is based on lever theory, loading testing apparatuswhich is made up of signal amplifier, modulus switch, battery detecting circuit, LCDand power sensor. Because of the complicated testing data processing, data processingsoftware is exploited with Visual Basic 6.0 which can exactly calculate testing data anddirectly attain testing report. On the side, it can be operated simply and its interface issimple and convenient. So software can greatly lighten testing personnel work intensionand testing apparatus become a suit of celerity and effective Ev2 testing system with it.