古建筑风化石质构件力学参数的确定方法

针对目前常规确定岩石力学参数的方法只能得出岩块的整体强度，不能反映古建筑石质构件风化层内力学参数逐渐变化，无法很好地满足石质古建筑稳定性、耐久性研究的不足，提出了综合运用现场穿透波CT测试、表面回弹测试和室内试验确定风化石质构件力学参数的方法。方法的实施主要包括：通过现场穿透波CT测试，获得纵波波速在石质构件深度剖面上的分布；现场选取与欲研究的石质构件类似的岩石做室内力学试验和波速测试，得出力学参数与波速的统计关系；上述两者结合得出力学参数在石质构件深度剖面上的分布，在此基础上分析风化层内力学参数随深度的变化关系；对不同风化分区代表性石构件进行风化深度研究和表面回弹测试，得出构件表面强度比与风化深度的关系。以义乌宋代古月桥为例，对其方法进行了系统的介绍，并对古月桥承载条石风化层内力学参数随深度的变化关系以及表面强度与风化深度的关系进行了研究。研究表明：义乌宋代古月桥承载条石风化层内的抗压强度比、弹性模量比随深度呈负指数关系变化；表面强度比与风化深度呈2次多项式关系。

Methods to obtain mechanical parameters of weathered rock constructional elements of ancient buildings

The conventional method of determining rock mechanical parameters now can only obtain the overall strength of the rock; while in the weathered layer of ancient buildings rock constructional elements, of which the mechanical parameters gradually change. It is not enough to study the stability and durability of rock ancient buildings. So a method with integrated use of on-site sonic CT test, surface rebound and laboratory test to obtain the mechanical parameters of rock constructional elements is proposed. The method is put into action as follows. The longitudinal wave velocity distributions along the depth profile in the rock constructional elements are acquired by the on-site sonic CT test. The statistical relation of the mechanical parameters and wave velocity is obtained by selecting rock on-site that analogous to the rock constructional element studied to do the indoor mechanical tests and the wave velocity test. The mechanical parameters distribution along the depth profile in the rock constructional elements is derived by combining the outcomes mentioned above; based on this, the relationship between mechanical parameters and depth within the weathered layer is analyzed. The relationship between the surface compressive strength ratio and the weathered depth is derived by weathered depth studying and surface rebound test on the typical rock constructional element in different weathering zones. This method is systematically introduced in this paper with the example of Guyue Bridge in Yiwu built in the Song Dynasty. This paper studied the relationship between mechanical parameters and depth within the weathered layer and the relationship between surface strength of rock constructional element and weathered depth of weathered rock constructional element which were in the bearing structure of the Song Dynasty Guyue Bridge in Yiwu. The studies show that: in the bearing block stone of the Song Dynasty Guyue Bridge, the compressive strength ratio and the elastic modulus ratio vary negative-exponentially with the depth in weathered layer; the relationship between compressive strength ratio of surface and weathered depth conforms to the two order polynomial.