【作者】 冯苍旭；

【导师】 张曙光；

【作者基本信息】 河北农业大学 ， 农业机械化工程， 2004， 硕士

【摘要】 土壤含水率测量是个应用广泛和潜力巨大的课题，涉及到农业、工业等国民经济的许多领域；孔隙水压力测量是一相对较新的领域，和农业、地质灾害关系密切。土壤含水率和孔隙水压力二者之间既相互区别，又相互联系。土壤含水率测量和孔隙水压力测量有专用方法和设备，但如果用于地质灾害的长期监测中，又都有其缺点和不足。因此我们开始新型孔隙水压力监测系统的研制工作。该系统主要是针对滑坡监测而研制的，但其同样可以在农业中得到应用。新型孔隙水压力监测系统，包括复合式探头、主机、通讯电缆、控制软件和数据处理软件；其中主机部分由测量电路、数据存储、自动控制及通讯接口组成；控制软件包括前端机自控软件、通讯协议。压力陶瓷探头是本系统的关键部件，也是其创新点，其中压力传感器是探头的核心部件。为了找到性价比高的压力传感器，对国内航天部某研究所研制的压力传感器和美国IC公司的压力传感器做了长期的对比性实验，在相同价位和满足条件的情况下，选用了美国IC公司的压力传感器。陶瓷外壳是探头的关键部件，是我们自行研制的。压力陶瓷探头的原理是：当陶瓷筒被水浸润后，孔隙间形成一层水膜，水可通过，但在一定压差下，可阻止空气通过，即不会漏气。用密封充水的微孔陶瓷筒观测土体对水分的吸力，即筒内形成的负压值，最终得到土体的含水率。陶瓷筒的孔隙越小，测量的范围越大，其透水性就差，反映迟钝，达到稳定负压值所需时间越长；孔隙大，测量范围小，但反映快，达到稳定负压值所需时间越短。经过我们长时间的反复实验，把测量范围和稳定时间综合考虑，采用了最大负压值可测到—80Kpa(800厘米水柱)空隙度的陶瓷筒。加了陶瓷外壳的压力传感器，既可以测饱和土壤中孔隙水的正压力，又可以测不饱和土壤中孔隙水的负压力。大家都知道测出的孔隙水负压力和土壤含水率之间有一定的关系，但它们之间具体的数学模型，由于涉及的因素较多，比如土体的结构、粒度等，都对模型有影响，因此国内和国际上一直没有定论。本研究在分析试验数据、仪器监测数据和前人结论的基础上，得出了一种算法，该算法主要针对颗粒直径在0.1-0.2MM、松散结构的土体，该土体是模拟长江三峡地区滑带处的土体特征而构建的。根据该算法编写的软件，应用于三峡地区的滑坡地质灾害监测中，取得了不错的效果。论文最后介绍了软件的流程图，并附有部分程序。更多还原

【Abstract】 The soil moisture measuring is the subject which has huge potential and extensive useness. It is often used in the agriculture and industry. The study of the pore water pressure is a relatively younger subject which is more related with agriculture and geological disaster. The soil moisture and the pore water pressure have some common ground. But they are quite different on almost all aspects. The paper first introduce several methods which is often used in measuring soil moisture and pore water pressure and analyze their strongpoint and fault. On the basis of this, the paper introduce a new style of pore water pressure monitoring system which made by Institute of Hydrogeology and Engineering geology Techniques, CGS. The system is studied for the purpose of monitoring coast, but it can also be used in the agriculture.The monitoring system includes the multi-sensor, the field instrument,the communication cable,the controlling software and the data managing software. The field instrument consistsof measuring circuit, data memory, automatic controlling and communication interface. The controlling software includes the field instrument’s self-control software and the communication protocol. The ceramic pressure sensor is the key components. It is the innovation of the system. The pressure sensor is the important component of the sensor. In order to search for the mos fitting pressure sensor for the performance and price,we worked for a long time to compare the sensors made by domestic institute of aviation and the American IC company.At last we decided to apply the product of the IC company. The ceramic crust which is studied by ourselves is the key component of the sensor. The theory of ceramic pressure sensor is: after the ceramic crust was soaked, it forms a flat of water film during the pores. The water can go through the film, but the air cann’t go through it under some pressure difference. That is inside the ceramic sensor is vacuum. We observed the suction of the sealed ceramic canister which is full of water to the soil. The suction is equal to the negative pressure inside the canister. The pore of the ceramic crust is more small, the measuring range is more wide. But its infiltration get worse. The reflection is slow. The time to get a stable stateis long. We spend a great deal time on experiment. In the end, the most negative pressure of the ceramic pressure sensor is -80Kpa. The data coming from instrument may be negative or positive. The positive data is the water level of the saturated soil from thesensor to the surface .If the data is negative, they show the soil is not saturated. Because the mathematic relates to the soil’s construction and the size of the grains, the relation between the negative pore water pressure and the aquiferous rate of soil hasn’t a conclusion internationally. Through studing the data receiving from the systeml and the data of soil acquiferous rate receiving from lab, we conclude a arithmetic on the base of former achievement. The arithmetic is fit for the soil whose grains is 0.1-0.2MM and the construction of soil is loose. The type of soil simulate the Three Gorge area’s soil. Based on the arithmetic, we program a set of soft. The soft is used on the monitoring of Three Gorge’s geological disaster and get a good result. At last the paper introduces the soft’s flow chart and how to realize.更多还原