( 7 ) in the hot dry rock geothermal energy extraction system , the fracture width widen gradually with the heat extraction , after the system start to operate , in a month the width change rapidly , the growth rate exceed 100 % , and then the change become even , until 3 year , the variety is very small , almost towards to stability ( 7 )在高温岩体地热开发中，其裂缝宽度是随地热提取而逐渐加宽的，在开始运行的一年内，宽度增长迅速，其增长率达到100 %以上，然后变得平缓，到3年后，变化很小，几乎趋于稳定。
The characteristic of excitation of the acoustic field is investigated for sources with various frequencies . the effects of an isotropic medium , inclined formation of different azimuth , horizontal or vertical fracture and its width or density on the propagation of the acoustic field are investigated . the fluid in borehole is also investigated 研究了声源在不同频率下的声场激发特性，考察了井外介质为均匀介质、存在不同倾角的地层界面、存在水平和垂直裂缝以及裂缝宽度和密度等对井内外声场传播的影响以及井眼流体对井孔声场的影响。
Thirdly , according to the conclusion of some experimentations that the maximum crack width and rebar section loss keep a approximate linear relationship after cover initial crack , a relationship between the maximum crack width and rebar section loss is developed based on a hypothesis that the increase in the volume of crack is equal to the volume of the corrosion products produced after cover initial crack 第三，根据钢筋在保护层开裂后继续锈蚀过程中产生的锈蚀产物填满裂缝的假设，建立锈胀开裂后裂缝宽度和钢筋锈蚀量之间的关系。第四，在钢筋年锈蚀速度为恒定值的基础上，建立从钢筋锈蚀开始到保护裂缝宽度发展至限制值所需时间的计算模型。
